31897989 has 8 divisors (see below), whose sum is σ = 47256320. Its totient is φ = 21265308.

The previous prime is 31897981. The next prime is 31897991. The reversal of 31897989 is 98979813.

It is not a de Polignac number, because 31897989 - 2³ = 31897981 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 (31897981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 590677 + ... + 590730.

It is an arithmetic number, because the mean of its divisors is an integer number (5907040).

Almost surely, 2^31897989 is an apocalyptic number.

It is an amenable number.

31897989 is a deficient number, since it is larger than the sum of its proper divisors (15358331).

31897989 is a wasteful number, since it uses less digits than its factorization.

31897989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1181416 (or 1181410 counting only the distinct ones).

The product of its digits is 979776, while the sum is 54.

The square root of 31897989 is about 5647.8304684188. The cubic root of 31897989 is about 317.1424921732.

The spelling of 31897989 in words is "thirty-one million, eight hundred ninety-seven thousand, nine hundred eighty-nine".