31087728 has 60 divisors (see below), whose sum is σ = 99434608. Its totient is φ = 8881920.

The previous prime is 31087711. The next prime is 31087751. The reversal of 31087728 is 82778013.

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

It is a junction number, because it is equal to n+sod(n) for n = 31087692 and 31087701.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14413 + ... + 16428.

Almost surely, 2^31087728 is an apocalyptic number.

It is an amenable number.

31087728 is an abundant number, since it is smaller than the sum of its proper divisors (68346880).

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

31087728 is a wasteful number, since it uses less digits than its factorization.

31087728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30862 (or 30853 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 31087728 is about 5575.6370039665. The cubic root of 31087728 is about 314.4341162986.

The spelling of 31087728 in words is "thirty-one million, eighty-seven thousand, seven hundred twenty-eight".