31931157 has 4 divisors (see below), whose sum is σ = 42574880. Its totient is φ = 21287436.

The previous prime is 31931071. The next prime is 31931167. The reversal of 31931157 is 75113913.

It is a happy number.

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 not a de Polignac number, because 31931157 - 2¹¹ = 31929109 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 (31931167) 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, 5321857 + ... + 5321862.

It is an arithmetic number, because the mean of its divisors is an integer number (10643720).

Almost surely, 2^31931157 is an apocalyptic number.

It is an amenable number.

31931157 is a deficient number, since it is larger than the sum of its proper divisors (10643723).

31931157 is a wasteful number, since it uses less digits than its factorization.

31931157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10643722.

The product of its digits is 2835, while the sum is 30.

The square root of 31931157 is about 5650.7660542620. The cubic root of 31931157 is about 317.2523772442.

The spelling of 31931157 in words is "thirty-one million, nine hundred thirty-one thousand, one hundred fifty-seven".