55565561 has 4 divisors (see below), whose sum is σ = 55593972. Its totient is φ = 55537152.

The previous prime is 55565533. The next prime is 55565563. The reversal of 55565561 is 16556555.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8231161 + 47334400 = 2869^2 + 6880^2 .

It is a cyclic number.

It is not a de Polignac number, because 55565561 - 2¹⁴ = 55549177 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (55565563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11036 + ... + 15261.

It is an arithmetic number, because the mean of its divisors is an integer number (13898493).

Almost surely, 2^55565561 is an apocalyptic number.

It is an amenable number.

55565561 is a deficient number, since it is larger than the sum of its proper divisors (28411).

55565561 is a wasteful number, since it uses less digits than its factorization.

55565561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28410.

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

The square root of 55565561 is about 7454.2310803999. The cubic root of 55565561 is about 381.5943195589.

The spelling of 55565561 in words is "fifty-five million, five hundred sixty-five thousand, five hundred sixty-one".