31809968 has 40 divisors (see below), whose sum is σ = 64757760. Its totient is φ = 15117120.

The previous prime is 31809961. The next prime is 31809977. The reversal of 31809968 is 86990813.

It is a super-2 number, since 2×31809968² = 2023748128322048, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (31809961) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28721 + ... + 29807.

It is an arithmetic number, because the mean of its divisors is an integer number (1618944).

Almost surely, 2^31809968 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31809968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32378880).

31809968 is an abundant number, since it is smaller than the sum of its proper divisors (32947792).

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

31809968 is a wasteful number, since it uses less digits than its factorization.

31809968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1185 (or 1179 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 44.

The square root of 31809968 is about 5640.0326240191. The cubic root of 31809968 is about 316.8505101757.

The spelling of 31809968 in words is "thirty-one million, eight hundred nine thousand, nine hundred sixty-eight".