55539877561 has 27 divisors (see below), whose sum is σ = 65358876207. Its totient is φ = 47058385920.

The previous prime is 55539877541. The next prime is 55539877571. The reversal of 55539877561 is 16577893555.

The square root of 55539877561 is 235669.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 54678807225 + 861070336 = 233835^2 + 29344^2 .

It is not a de Polignac number, because 55539877561 - 2¹³ = 55539869369 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 55539877561.

It is not an unprimeable number, because it can be changed into a prime (55539877511) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 216108345 + ... + 216108601.

Almost surely, 2^55539877561 is an apocalyptic number.

55539877561 is the 235669-th square number.

55539877561 is the 117835-th centered octagonal number.

It is an amenable number.

55539877561 is a deficient number, since it is larger than the sum of its proper divisors (9818998646).

55539877561 is an frugal number, since it uses more digits than its factorization.

55539877561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 790 (or 395 counting only the distinct ones).

The product of its digits is 39690000, while the sum is 61.

The spelling of 55539877561 in words is "fifty-five billion, five hundred thirty-nine million, eight hundred seventy-seven thousand, five hundred sixty-one".