55661566565 has 24 divisors (see below), whose sum is σ = 76902978528. Its totient is φ = 38350539360.

The previous prime is 55661566529. The next prime is 55661566567. The reversal of 55661566565 is 56566516655.

55661566565 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 55661566565 - 2¹⁴ = 55661550181 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 55661566565.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55661566567) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1381847 + ... + 1421556.

It is an arithmetic number, because the mean of its divisors is an integer number (3204290772).

Almost surely, 2^55661566565 is an apocalyptic number.

55661566565 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

It is an amenable number.

55661566565 is a deficient number, since it is larger than the sum of its proper divisors (21241411963).

55661566565 is a wasteful number, since it uses less digits than its factorization.

55661566565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2803457 (or 2803438 counting only the distinct ones).

The product of its digits is 24300000, while the sum is 56.

It can be divided in two parts, 55661 and 566565, that added together give a palindrome (622226).

The spelling of 55661566565 in words is "fifty-five billion, six hundred sixty-one million, five hundred sixty-six thousand, five hundred sixty-five".