165557755561 has 16 divisors (see below), whose sum is σ = 184042300608. Its totient is φ = 147646324800.

The previous prime is 165557755543. The next prime is 165557755579.

165557755561 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (165557755543) and next prime (165557755579).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165557755561 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 165557755496 and 165557755505.

It is not an unprimeable number, because it can be changed into a prime (165557755511) 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 15 ways as a sum of consecutive naturals, for example, 5284435 + ... + 5315671.

It is an arithmetic number, because the mean of its divisors is an integer number (11502643788).

Almost surely, 2^165557755561 is an apocalyptic number.

165557755561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165557755561 is a deficient number, since it is larger than the sum of its proper divisors (18484545047).

165557755561 is a wasteful number, since it uses less digits than its factorization.

165557755561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40392.

The product of its digits is 27562500, while the sum is 58.

The spelling of 165557755561 in words is "one hundred sixty-five billion, five hundred fifty-seven million, seven hundred fifty-five thousand, five hundred sixty-one".