56728021 has 8 divisors (see below), whose sum is σ = 64895040. Its totient is φ = 48576768.

The previous prime is 56728003. The next prime is 56728027. The reversal of 56728021 is 12082765.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 56728021 - 2⁵ = 56727989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56728027) 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, 5190 + ... + 11848.

It is an arithmetic number, because the mean of its divisors is an integer number (8111880).

Almost surely, 2^56728021 is an apocalyptic number.

It is an amenable number.

56728021 is a deficient number, since it is larger than the sum of its proper divisors (8167019).

56728021 is a wasteful number, since it uses less digits than its factorization.

56728021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7883.

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 56728021 is about 7531.8006479195. The cubic root of 56728021 is about 384.2370249800.

The spelling of 56728021 in words is "fifty-six million, seven hundred twenty-eight thousand, twenty-one".