51656565161 has 4 divisors (see below), whose sum is σ = 51732197712. Its totient is φ = 51580932612.

The previous prime is 51656565151. The next prime is 51656565197. The reversal of 51656565161 is 16156565615.

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 51656565161 - 2¹⁴ = 51656548777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51656565101) 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, 37815251 + ... + 37816616.

It is an arithmetic number, because the mean of its divisors is an integer number (12933049428).

Almost surely, 2^51656565161 is an apocalyptic number.

It is an amenable number.

51656565161 is a deficient number, since it is larger than the sum of its proper divisors (75632551).

51656565161 is an equidigital number, since it uses as much as digits as its factorization.

51656565161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75632550.

The product of its digits is 810000, while the sum is 47.

The spelling of 51656565161 in words is "fifty-one billion, six hundred fifty-six million, five hundred sixty-five thousand, one hundred sixty-one".