56551661 has 4 divisors (see below), whose sum is σ = 56652672. Its totient is φ = 56450652.

The previous prime is 56551613. The next prime is 56551699. The reversal of 56551661 is 16615565.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16615565 = 5 ⋅3323113.

It is a cyclic number.

It is not a de Polignac number, because 56551661 - 2¹⁸ = 56289517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56551361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49661 + ... + 50786.

It is an arithmetic number, because the mean of its divisors is an integer number (14163168).

Almost surely, 2^56551661 is an apocalyptic number.

It is an amenable number.

56551661 is a deficient number, since it is larger than the sum of its proper divisors (101011).

56551661 is a wasteful number, since it uses less digits than its factorization.

56551661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101010.

The product of its digits is 27000, while the sum is 35.

The square root of 56551661 is about 7520.0838426177. The cubic root of 56551661 is about 383.8384307447.

The spelling of 56551661 in words is "fifty-six million, five hundred fifty-one thousand, six hundred sixty-one".