Every Day Counts
Centred Triangular Prime Days
 
Age: 20,008 days
Date of birth
Your 27th Centred Triangular Prime Day is on
Monday
when you will be
20,011 days old

A centred triangular prime is a centred triangular number that is prime.

Centred triangular numbers are of the form (3n2 + 3n + 2) / 2

A centred triangular number is a centred figurate number that represents a triangle with a dot in the centre and all other dots surrounding the centre in successive triangular layers.

The figures for the first four centred triangular numbers are shown below:

Remind me, please


Next Prime Events
Day Age
Event
Days Ahead
Year Age
15 Dec 2025
20,011
3
54
15 Dec 2025
20,011
3
54
23 Jun 2026
20,201
193
55
26 Nov 2026
20,357
349
55
01 Aug 2030
21,701
1,693
59
16 Aug 2032
22,447
2,439
61
17 Aug 2049
28,657
8,649
78
02 Aug 2053
30,103
10,095
82
05 Jan 2073
37,199
17,191
101
13 Dec 2078
39,367
19,359
107
14 Nov 2090
43,721
23,713
119
13 Apr 2104
48,619
28,611
133
08 Aug 2150
65,537
45,529
179
21 Sep 2245
100,279
80,271
274
10 Apr 2269
108,881
88,873
298
11 Jan 2330
131,071
111,063
358
04 May 7788
2,124,679
2,104,671
5817
Ordinal
Day Age
Date
Age
1st
19
22 Mar 1971
0
2nd
31
03 Apr 1971
0
3rd
109
20 Jun 1971
0
4th
199
18 Sep 1971
0
5th
409
15 Apr 1972
1
6th
571
24 Sep 1972
1
7th
631
23 Nov 1972
1
8th
829
09 Jun 1973
2
9th
1,489
31 Mar 1975
4
10th
1,999
22 Aug 1976
5
11th
2,341
30 Jul 1977
6
12th
2,971
21 Apr 1979
8
13th
3,529
30 Oct 1980
9
14th
4,621
27 Oct 1983
12
15th
4,789
12 Apr 1984
13
16th
7,039
10 Jun 1990
19
17th
7,669
01 Mar 1992
20
18th
8,779
16 Mar 1995
24
19th
9,721
13 Oct 1997
26
20th
10,459
21 Oct 1999
28
21st
10,711
29 Jun 2000
29
22nd
13,681
16 Aug 2008
37
23rd
14,851
30 Oct 2011
40
24th
16,069
01 Mar 2015
43
25th
16,381
07 Jan 2016
44
26th
17,659
08 Jul 2019
48
27th
20,011
15 Dec 2025
54
1
28th
20,359
28 Nov 2026
55
29th
23,251
29 Oct 2034
63
30th
25,939
09 Mar 2042
71
31st
27,541
28 Jul 2046
75
32nd
29,191
02 Feb 2051
79
33rd
29,611
28 Mar 2052
81
34th
31,321
02 Dec 2056
85
35th
34,429
06 Jun 2065
94
36th
36,739
03 Oct 2071
100
37th
40,099
14 Dec 2080
109
38th
40,591
20 Apr 2082
111
39th
42,589
09 Oct 2087
116