55556561 has 16 divisors (see below), whose sum is σ = 60431184. Its totient is φ = 50878464.

The previous prime is 55556521. The next prime is 55556581. The reversal of 55556561 is 16565555.

It can be written as a sum of positive squares in 8 ways, for example, as 2907025 + 52649536 = 1705^2 + 7256^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55556561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55556521) 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, 177341 + ... + 177653.

It is an arithmetic number, because the mean of its divisors is an integer number (3776949).

Almost surely, 2^55556561 is an apocalyptic number.

It is an amenable number.

55556561 is a deficient number, since it is larger than the sum of its proper divisors (4874623).

55556561 is a wasteful number, since it uses less digits than its factorization.

55556561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 580.

The product of its digits is 112500, while the sum is 38.

The square root of 55556561 is about 7453.6273719579. The cubic root of 55556561 is about 381.5737160637.

The spelling of 55556561 in words is "fifty-five million, five hundred fifty-six thousand, five hundred sixty-one".