31920768 has 144 divisors (see below), whose sum is σ = 101405850. Its totient is φ = 9630720.

The previous prime is 31920761. The next prime is 31920797. The reversal of 31920768 is 86702913.

It can be written as a sum of positive squares in only one way, i.e., 20142144 + 11778624 = 4488^2 + 3432^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (31920761) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 139278 + ... + 139506.

Almost surely, 2^31920768 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 31920768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50702925).

31920768 is an abundant number, since it is smaller than the sum of its proper divisors (69485082).

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

31920768 is a wasteful number, since it uses less digits than its factorization.

31920768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 271 (or 245 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 31920768 is about 5649.8467235846. The cubic root of 31920768 is about 317.2179668357.

31920768 divided by its sum of digits (36) gives a palindrome (886688).

The spelling of 31920768 in words is "thirty-one million, nine hundred twenty thousand, seven hundred sixty-eight".