31915989 has 24 divisors (see below), whose sum is σ = 53114880. Its totient is φ = 18089568.

The previous prime is 31915967. The next prime is 31916009. The reversal of 31915989 is 98951913.

It is not a de Polignac number, because 31915989 - 2⁸ = 31915733 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31913989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6007 + ... + 9995.

It is an arithmetic number, because the mean of its divisors is an integer number (2213120).

Almost surely, 2^31915989 is an apocalyptic number.

It is an amenable number.

31915989 is a deficient number, since it is larger than the sum of its proper divisors (21198891).

31915989 is a wasteful number, since it uses less digits than its factorization.

31915989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4129 (or 4126 counting only the distinct ones).

The product of its digits is 87480, while the sum is 45.

The square root of 31915989 is about 5649.4237759262. The cubic root of 31915989 is about 317.2021353419.

It can be divided in two parts, 3191 and 5989, that added together give a triangular number (9180 = T₁₃₅).

The spelling of 31915989 in words is "thirty-one million, nine hundred fifteen thousand, nine hundred eighty-nine".