2155634351561 has 4 divisors (see below), whose sum is σ = 2155646946432. Its totient is φ = 2155621756692.

The previous prime is 2155634351531. The next prime is 2155634351627. The reversal of 2155634351561 is 1651534365512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2155634351561 - 2³⁰ = 2154560609737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2155634351501) 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, 6037121 + ... + 6384206.

It is an arithmetic number, because the mean of its divisors is an integer number (538911736608).

Almost surely, 2^{2155634351561} is an apocalyptic number.

It is an amenable number.

2155634351561 is a deficient number, since it is larger than the sum of its proper divisors (12594871).

2155634351561 is a wasteful number, since it uses less digits than its factorization.

2155634351561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12594870.

The product of its digits is 1620000, while the sum is 47.

The spelling of 2155634351561 in words is "two trillion, one hundred fifty-five billion, six hundred thirty-four million, three hundred fifty-one thousand, five hundred sixty-one".