31897231 has 2 divisors, whose sum is σ = 31897232. Its totient is φ = 31897230.

The previous prime is 31897207. The next prime is 31897259. The reversal of 31897231 is 13279813.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31897231 - 2⁵ = 31897199 is a prime.

It is a super-2 number, since 2×31897231² = 2034866690934722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31897291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15948615 + 15948616.

It is an arithmetic number, because the mean of its divisors is an integer number (15948616).

Almost surely, 2^31897231 is an apocalyptic number.

31897231 is a deficient number, since it is larger than the sum of its proper divisors (1).

31897231 is an equidigital number, since it uses as much as digits as its factorization.

31897231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 34.

The square root of 31897231 is about 5647.7633626065. The cubic root of 31897231 is about 317.1399800408.

The spelling of 31897231 in words is "thirty-one million, eight hundred ninety-seven thousand, two hundred thirty-one".