3131521728 has 28 divisors (see below), whose sum is σ = 8285485080. Its totient is φ = 1043840512.

The previous prime is 3131521667. The next prime is 3131521733. The reversal of 3131521728 is 8271251313.

It is a happy number.

3131521728 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×3131521728² = 19612856665872211968, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8154813 + ... + 8155196.

Almost surely, 2^3131521728 is an apocalyptic number.

It is an amenable number.

3131521728 is an abundant number, since it is smaller than the sum of its proper divisors (5153963352).

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

3131521728 is a wasteful number, since it uses less digits than its factorization.

3131521728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16310024 (or 16310014 counting only the distinct ones).

The product of its digits is 10080, while the sum is 33.

The square root of 3131521728 is about 55960.0011436740. The cubic root of 3131521728 is about 1463.0252103275.

The spelling of 3131521728 in words is "three billion, one hundred thirty-one million, five hundred twenty-one thousand, seven hundred twenty-eight".