# 13

This number is a prime.

Just showing those entries submitted by 'Gupta': (Click here to show all)

Photo credit: Patrick Kik |

The smallest prime whose sum of digits is a square. [Gupta]

A concatenation of the first two triangular numbers. [Gupta]

The sum of first 13 prime numbers is 238 (whose sum of digits is 13). [Gupta]

The smallest prime that can be expressed as the sum of two primes (2 + 11) and two composites (4 + 9) in only one way. [Gupta]

π(13) = 1! * 3!. [Gupta]

Currently (between the years 1901 and 2099) the Julian calendar is 13 days behind the Gregorian calendar. [Gupta]

This is the only prime p such that 2*p+1 is a cube. [Gupta]

A February 'Friday the 13th' in a leap year occurs just 13 times within a 400-year period. [Gupta]

Floor function of π*e*phi, where phi is the golden ratio. [Gupta]

The longest known sequence of consecutive primes with distinct digits starts from 13. [Gupta]