31605138 has 24 divisors (see below), whose sum is σ = 69146688. Its totient is φ = 10432152.

The previous prime is 31605127. The next prime is 31605139. The reversal of 31605138 is 83150613.

It is not an unprimeable number, because it can be changed into a prime (31605139) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6670 + ... + 10377.

It is an arithmetic number, because the mean of its divisors is an integer number (2881112).

Almost surely, 2^31605138 is an apocalyptic number.

31605138 is an abundant number, since it is smaller than the sum of its proper divisors (37541550).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31605138 is a wasteful number, since it uses less digits than its factorization.

31605138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17158 (or 17155 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 31605138 is about 5621.8447150379. The cubic root of 31605138 is about 316.1689597429.

The spelling of 31605138 in words is "thirty-one million, six hundred five thousand, one hundred thirty-eight".