56639987 has 16 divisors (see below), whose sum is σ = 61158240. Its totient is φ = 52346112.

The previous prime is 56639981. The next prime is 56640011. The reversal of 56639987 is 78993665.

It is a cyclic number.

It is not a de Polignac number, because 56639987 - 2⁶ = 56639923 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (53).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (56639981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65663 + ... + 66519.

It is an arithmetic number, because the mean of its divisors is an integer number (3822390).

Almost surely, 2^56639987 is an apocalyptic number.

56639987 is a deficient number, since it is larger than the sum of its proper divisors (4518253).

56639987 is a wasteful number, since it uses less digits than its factorization.

56639987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 982.

The product of its digits is 2449440, while the sum is 53.

The square root of 56639987 is about 7525.9542252129. The cubic root of 56639987 is about 384.0381612646.

The spelling of 56639987 in words is "fifty-six million, six hundred thirty-nine thousand, nine hundred eighty-seven".