31687872 has 28 divisors (see below), whose sum is σ = 83841336. Its totient is φ = 10562560.

The previous prime is 31687871. The next prime is 31687879. The reversal of 31687872 is 27878613.

It is not an unprimeable number, because it can be changed into a prime (31687871) 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, 82329 + ... + 82712.

Almost surely, 2^31687872 is an apocalyptic number.

31687872 is a gapful number since it is divisible by the number (32) formed by its first and last digit.

It is an amenable number.

31687872 is an abundant number, since it is smaller than the sum of its proper divisors (52153464).

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

31687872 is a wasteful number, since it uses less digits than its factorization.

31687872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165056 (or 165046 counting only the distinct ones).

The product of its digits is 112896, while the sum is 42.

The square root of 31687872 is about 5629.1981667019. The cubic root of 31687872 is about 316.4446019605. Note that the first 3 decimals are identical.

It can be divided in two parts, 316 and 87872, that added together give a palindrome (88188).

The spelling of 31687872 in words is "thirty-one million, six hundred eighty-seven thousand, eight hundred seventy-two".