31257013 has 4 divisors (see below), whose sum is σ = 31339008. Its totient is φ = 31175020.

The previous prime is 31256987. The next prime is 31257019. The reversal of 31257013 is 31075213.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31257013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31257019) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40423 + ... + 41188.

It is an arithmetic number, because the mean of its divisors is an integer number (7834752).

Almost surely, 2^31257013 is an apocalyptic number.

It is an amenable number.

31257013 is a deficient number, since it is larger than the sum of its proper divisors (81995).

31257013 is an equidigital number, since it uses as much as digits as its factorization.

31257013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81994.

The product of its (nonzero) digits is 630, while the sum is 22.

The square root of 31257013 is about 5590.7971703506. The cubic root of 31257013 is about 315.0038229149.

The spelling of 31257013 in words is "thirty-one million, two hundred fifty-seven thousand, thirteen".