31328857 has 4 divisors (see below), whose sum is σ = 35804416. Its totient is φ = 26853300.

The previous prime is 31328833. The next prime is 31328861. The reversal of 31328857 is 75882313.

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-31328857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31328827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2237769 + ... + 2237782.

It is an arithmetic number, because the mean of its divisors is an integer number (8951104).

Almost surely, 2^31328857 is an apocalyptic number.

It is an amenable number.

31328857 is a deficient number, since it is larger than the sum of its proper divisors (4475559).

31328857 is an equidigital number, since it uses as much as digits as its factorization.

31328857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4475558.

The product of its digits is 40320, while the sum is 37.

The square root of 31328857 is about 5597.2186843110. The cubic root of 31328857 is about 315.2449828491.

The spelling of 31328857 in words is "thirty-one million, three hundred twenty-eight thousand, eight hundred fifty-seven".