165519915561 has 128 divisors (see below), whose sum is σ = 329936302080. Its totient is φ = 79202188800.

The previous prime is 165519915493. The next prime is 165519915563.

It is a happy number.

165519915561 is a `hidden beast` number, since 1 + 6 + 55 + 19 + 9 + 15 + 561 = 666.

165519915561 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 165519915561 - 2¹¹ = 165519913513 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 165519915498 and 165519915507.

It is not an unprimeable number, because it can be changed into a prime (165519915563) 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 127 ways as a sum of consecutive naturals, for example, 13264021 + ... + 13276493.

It is an arithmetic number, because the mean of its divisors is an integer number (2577627360).

Almost surely, 2^165519915561 is an apocalyptic number.

165519915561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165519915561 is a deficient number, since it is larger than the sum of its proper divisors (164416386519).

165519915561 is a wasteful number, since it uses less digits than its factorization.

165519915561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13004 (or 12998 counting only the distinct ones).

The product of its digits is 1822500, while the sum is 54.

The spelling of 165519915561 in words is "one hundred sixty-five billion, five hundred nineteen million, nine hundred fifteen thousand, five hundred sixty-one".