31989531 has 8 divisors (see below), whose sum is σ = 48745984. Its totient is φ = 18279720.

The previous prime is 31989493. The next prime is 31989541. The reversal of 31989531 is 13598913.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 31989531 - 2¹⁵ = 31956763 is a prime.

It is a super-2 number, since 2×31989531² = 2046660187199922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31989531.

It is not an unprimeable number, because it can be changed into a prime (31989541) 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, 761635 + ... + 761676.

It is an arithmetic number, because the mean of its divisors is an integer number (6093248).

Almost surely, 2^31989531 is an apocalyptic number.

31989531 is a deficient number, since it is larger than the sum of its proper divisors (16756453).

31989531 is a wasteful number, since it uses less digits than its factorization.

31989531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1523321.

The product of its digits is 29160, while the sum is 39.

The square root of 31989531 is about 5655.9288361860. The cubic root of 31989531 is about 317.4455847390.

The spelling of 31989531 in words is "thirty-one million, nine hundred eighty-nine thousand, five hundred thirty-one".