55551565566 has 96 divisors (see below), whose sum is σ = 143589888000. Its totient is φ = 15187201920.

The previous prime is 55551565561. The next prime is 55551565579. The reversal of 55551565566 is 66556515555.

55551565566 is a `hidden beast` number, since 5 + 5 + 5 + 5 + 15 + 65 + 566 = 666.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55551565561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 267735 + ... + 427533.

It is an arithmetic number, because the mean of its divisors is an integer number (1495728000).

Almost surely, 2^55551565566 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 55551565566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (71794944000).

55551565566 is an abundant number, since it is smaller than the sum of its proper divisors (88038322434).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

55551565566 is a wasteful number, since it uses less digits than its factorization.

55551565566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159934 (or 159931 counting only the distinct ones).

The product of its digits is 16875000, while the sum is 54.

The spelling of 55551565566 in words is "fifty-five billion, five hundred fifty-one million, five hundred sixty-five thousand, five hundred sixty-six".