31390657 has 4 divisors (see below), whose sum is σ = 31820740. Its totient is φ = 30960576.

The previous prime is 31390637. The next prime is 31390691. The reversal of 31390657 is 75609313.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 25441936 + 5948721 = 5044^2 + 2439^2 .

It is a cyclic number.

It is not a de Polignac number, because 31390657 - 2⁷ = 31390529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31390627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 214932 + ... + 215077.

It is an arithmetic number, because the mean of its divisors is an integer number (7955185).

Almost surely, 2^31390657 is an apocalyptic number.

It is an amenable number.

31390657 is a deficient number, since it is larger than the sum of its proper divisors (430083).

31390657 is an equidigital number, since it uses as much as digits as its factorization.

31390657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430082.

The product of its (nonzero) digits is 17010, while the sum is 34.

The square root of 31390657 is about 5602.7365635018. The cubic root of 31390657 is about 315.4521331202.

The spelling of 31390657 in words is "thirty-one million, three hundred ninety thousand, six hundred fifty-seven".