31897931 has 4 divisors (see below), whose sum is σ = 34351632. Its totient is φ = 29444232.

The previous prime is 31897927. The next prime is 31897949. The reversal of 31897931 is 13979813.

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

It is a cyclic number.

It is not a de Polignac number, because 31897931 - 2² = 31897927 is a prime.

It is a super-2 number, since 2×31897931² = 2034956004161522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31897951) 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, 1226831 + ... + 1226856.

It is an arithmetic number, because the mean of its divisors is an integer number (8587908).

Almost surely, 2^31897931 is an apocalyptic number.

31897931 is a deficient number, since it is larger than the sum of its proper divisors (2453701).

31897931 is a wasteful number, since it uses less digits than its factorization.

31897931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2453700.

The product of its digits is 40824, while the sum is 41.

The square root of 31897931 is about 5647.8253337015. The cubic root of 31897931 is about 317.1422999534.

The spelling of 31897931 in words is "thirty-one million, eight hundred ninety-seven thousand, nine hundred thirty-one".