165651015660561 has 32 divisors (see below), whose sum is σ = 247662921968000. Its totient is φ = 109419726878784.

The previous prime is 165651015660553. The next prime is 165651015660563. The reversal of 165651015660561 is 165066510156561.

165651015660561 is a `hidden beast` number, since 1 + 6 + 5 + 6 + 5 + 1 + 0 + 15 + 6 + 60 + 561 = 666.

It is not a de Polignac number, because 165651015660561 - 2³ = 165651015660553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 165651015660498 and 165651015660507.

It is not an unprimeable number, because it can be changed into a prime (165651015660563) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 362434566 + ... + 362891328.

It is an arithmetic number, because the mean of its divisors is an integer number (7739466311500).

Almost surely, 2^{165651015660561} is an apocalyptic number.

It is an amenable number.

165651015660561 is a deficient number, since it is larger than the sum of its proper divisors (82011906307439).

165651015660561 is a wasteful number, since it uses less digits than its factorization.

165651015660561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 580110 (or 580104 counting only the distinct ones).

The product of its (nonzero) digits is 4860000, while the sum is 54.

The spelling of 165651015660561 in words is "one hundred sixty-five trillion, six hundred fifty-one billion, fifteen million, six hundred sixty thousand, five hundred sixty-one".