31120728 has 32 divisors (see below), whose sum is σ = 77938800. Its totient is φ = 10355328.

The previous prime is 31120723. The next prime is 31120751. The reversal of 31120728 is 82702113.

It is a super-2 number, since 2×31120728² = 1936999422499968, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a junction number, because it is equal to n+sod(n) for n = 31120698 and 31120707.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31120723) 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, 25050 + ... + 26262.

Almost surely, 2^31120728 is an apocalyptic number.

It is an amenable number.

31120728 is an abundant number, since it is smaller than the sum of its proper divisors (46818072).

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

31120728 is a wasteful number, since it uses less digits than its factorization.

31120728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2291 (or 2287 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 31120728 is about 5578.5955221722. The cubic root of 31120728 is about 314.5453354960.

The spelling of 31120728 in words is "thirty-one million, one hundred twenty thousand, seven hundred twenty-eight".