165915519561 has 72 divisors (see below), whose sum is σ = 272883250080. Its totient is φ = 99557797680.

The previous prime is 165915519559. The next prime is 165915519571.

It is a happy number.

165915519561 is a `hidden beast` number, since 1 + 6 + 59 + 15 + 5 + 19 + 561 = 666.

165915519561 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 165915519561 - 2¹ = 165915519559 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 165915519498 and 165915519507.

It is not an unprimeable number, because it can be changed into a prime (165915519571) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 34657210 + ... + 34661996.

It is an arithmetic number, because the mean of its divisors is an integer number (3790045140).

Almost surely, 2^165915519561 is an apocalyptic number.

165915519561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165915519561 is a deficient number, since it is larger than the sum of its proper divisors (106967730519).

165915519561 is a wasteful number, since it uses less digits than its factorization.

165915519561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5024 (or 4904 counting only the distinct ones).

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

The spelling of 165915519561 in words is "one hundred sixty-five billion, nine hundred fifteen million, five hundred nineteen thousand, five hundred sixty-one".