156505665561 has 64 divisors (see below), whose sum is σ = 246934433280. Its totient is φ = 86304890880.

The previous prime is 156505665553. The next prime is 156505665623. The reversal of 156505665561 is 165566505651.

It is not a de Polignac number, because 156505665561 - 2³ = 156505665553 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (156505665061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 113327091 + ... + 113328471.

It is an arithmetic number, because the mean of its divisors is an integer number (3858350520).

Almost surely, 2^156505665561 is an apocalyptic number.

It is an amenable number.

156505665561 is a deficient number, since it is larger than the sum of its proper divisors (90428767719).

156505665561 is a wasteful number, since it uses less digits than its factorization.

156505665561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2514.

The product of its (nonzero) digits is 4050000, while the sum is 51.

The spelling of 156505665561 in words is "one hundred fifty-six billion, five hundred five million, six hundred sixty-five thousand, five hundred sixty-one".