31905889 has 12 divisors (see below), whose sum is σ = 34228044. Its totient is φ = 29732864.

The previous prime is 31905857. The next prime is 31905893. The reversal of 31905889 is 98850913.

It can be written as a sum of positive squares in 6 ways, for example, as 1710864 + 30195025 = 1308^2 + 5495^2 .

It is not a de Polignac number, because 31905889 - 2⁵ = 31905857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31905089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32169 + ... + 33145.

It is an arithmetic number, because the mean of its divisors is an integer number (2852337).

Almost surely, 2^31905889 is an apocalyptic number.

It is an amenable number.

31905889 is a deficient number, since it is larger than the sum of its proper divisors (2322155).

31905889 is a wasteful number, since it uses less digits than its factorization.

31905889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1124 (or 1107 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 43.

The square root of 31905889 is about 5648.5298087201. The cubic root of 31905889 is about 317.1686716593.

The spelling of 31905889 in words is "thirty-one million, nine hundred five thousand, eight hundred eighty-nine".