56257821 has 10 divisors (see below), whose sum is σ = 84039582. Its totient is φ = 37505160.

The previous prime is 56257801. The next prime is 56257829. The reversal of 56257821 is 12875265.

It is a happy number.

56257821 is a `hidden beast` number, since 5 + 62 + 578 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 46049796 + 10208025 = 6786^2 + 3195^2 .

It is not a de Polignac number, because 56257821 - 2⁶ = 56257757 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56257829) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 347190 + ... + 347351.

Almost surely, 2^56257821 is an apocalyptic number.

It is an amenable number.

56257821 is a deficient number, since it is larger than the sum of its proper divisors (27781761).

56257821 is an equidigital number, since it uses as much as digits as its factorization.

56257821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 694553 (or 694544 counting only the distinct ones).

The product of its digits is 33600, while the sum is 36.

The square root of 56257821 is about 7500.5213818774. The cubic root of 56257821 is about 383.1724733177.

The spelling of 56257821 in words is "fifty-six million, two hundred fifty-seven thousand, eight hundred twenty-one".