31312613 has 2 divisors, whose sum is σ = 31312614. Its totient is φ = 31312612.

The previous prime is 31312597. The next prime is 31312679. The reversal of 31312613 is 31621313.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27384289 + 3928324 = 5233^2 + 1982^2 .

It is a cyclic number.

It is not a de Polignac number, because 31312613 - 2⁴ = 31312597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31342613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15656306 + 15656307.

It is an arithmetic number, because the mean of its divisors is an integer number (15656307).

Almost surely, 2^31312613 is an apocalyptic number.

It is an amenable number.

31312613 is a deficient number, since it is larger than the sum of its proper divisors (1).

31312613 is an equidigital number, since it uses as much as digits as its factorization.

31312613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 324, while the sum is 20.

The square root of 31312613 is about 5595.7674183261. The cubic root of 31312613 is about 315.1904886299.

Adding to 31312613 its reverse (31621313), we get a palindrome (62933926).

It can be divided in two parts, 31 and 312613, that multiplied together give a triangular number (9691003 = T₄₄₀₂).

The spelling of 31312613 in words is "thirty-one million, three hundred twelve thousand, six hundred thirteen".