31638536 has 16 divisors (see below), whose sum is σ = 61368300. Its totient is φ = 15273664.

The previous prime is 31638533. The next prime is 31638557. The reversal of 31638536 is 63583613.

It can be written as a sum of positive squares in 2 ways, for example, as 30316036 + 1322500 = 5506^2 + 1150^2 .

It is a junction number, because it is equal to n+sod(n) for n = 31638496 and 31638505.

It is not an unprimeable number, because it can be changed into a prime (31638533) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67955 + ... + 68418.

Almost surely, 2^31638536 is an apocalyptic number.

It is an amenable number.

31638536 is a deficient number, since it is larger than the sum of its proper divisors (29729764).

31638536 is a wasteful number, since it uses less digits than its factorization.

31638536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136408 (or 136404 counting only the distinct ones).

The product of its digits is 38880, while the sum is 35.

The square root of 31638536 is about 5624.8143080461. The cubic root of 31638536 is about 316.2802886205.

The spelling of 31638536 in words is "thirty-one million, six hundred thirty-eight thousand, five hundred thirty-six".