165716617561 has 16 divisors (see below), whose sum is σ = 189497867328. Its totient is φ = 143558956800.

The previous prime is 165716617553. The next prime is 165716617597.

165716617561 is nontrivially palindromic in base 10.

It is a cyclic number.

It is not a de Polignac number, because 165716617561 - 2³ = 165716617553 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 165716617499 and 165716617508.

It is not an unprimeable number, because it can be changed into a prime (165716617361) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4253196 + ... + 4291981.

It is an arithmetic number, because the mean of its divisors is an integer number (11843616708).

Almost surely, 2^165716617561 is an apocalyptic number.

165716617561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165716617561 is a deficient number, since it is larger than the sum of its proper divisors (23781249767).

165716617561 is a wasteful number, since it uses less digits than its factorization.

165716617561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8545272.

The product of its digits is 1587600, while the sum is 52.

The spelling of 165716617561 in words is "one hundred sixty-five billion, seven hundred sixteen million, six hundred seventeen thousand, five hundred sixty-one".