31791728 has 20 divisors (see below), whose sum is σ = 63100128. Its totient is φ = 15507840.

The previous prime is 31791713. The next prime is 31791757. The reversal of 31791728 is 82719713.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 31791691 and 31791700.

It is a congruent number.

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, 23576 + ... + 24887.

Almost surely, 2^31791728 is an apocalyptic number.

It is an amenable number.

31791728 is a deficient number, since it is larger than the sum of its proper divisors (31308400).

31791728 is a wasteful number, since it uses less digits than its factorization.

31791728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48512 (or 48506 counting only the distinct ones).

The product of its digits is 21168, while the sum is 38.

The square root of 31791728 is about 5638.4153802287. The cubic root of 31791728 is about 316.7899373568.

The spelling of 31791728 in words is "thirty-one million, seven hundred ninety-one thousand, seven hundred twenty-eight".