55005561 has 20 divisors (see below), whose sum is σ = 88491172. Its totient is φ = 33848928.

The previous prime is 55005553. The next prime is 55005583. The reversal of 55005561 is 16550055.

55005561 is a `hidden beast` number, since 550 + 0 + 55 + 61 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 14288400 + 40717161 = 3780^2 + 6381^2 .

It is not a de Polignac number, because 55005561 - 2³ = 55005553 is a prime.

It is a super-2 number, since 2×55005561² = 6051223481849442, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55005521) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 25066 + ... + 27171.

Almost surely, 2^55005561 is an apocalyptic number.

It is an amenable number.

55005561 is a deficient number, since it is larger than the sum of its proper divisors (33485611).

55005561 is a wasteful number, since it uses less digits than its factorization.

55005561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52262 (or 52253 counting only the distinct ones).

The product of its (nonzero) digits is 3750, while the sum is 27.

The square root of 55005561 is about 7416.5734001626. The cubic root of 55005561 is about 380.3080627464.

The spelling of 55005561 in words is "fifty-five million, five thousand, five hundred sixty-one".