161556365455 has 32 divisors (see below), whose sum is σ = 206751771648. Its totient is φ = 120766272000.

The previous prime is 161556365417. The next prime is 161556365459. The reversal of 161556365455 is 554563655161.

It is not a de Polignac number, because 161556365455 - 2²¹ = 161554268303 is a prime.

It is a super-2 number, since 2×161556365455² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161556365459) 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, 34793364 + ... + 34798006.

It is an arithmetic number, because the mean of its divisors is an integer number (6460992864).

Almost surely, 2^161556365455 is an apocalyptic number.

161556365455 is a deficient number, since it is larger than the sum of its proper divisors (45195406193).

161556365455 is a wasteful number, since it uses less digits than its factorization.

161556365455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7527.

The product of its digits is 8100000, while the sum is 52.

The spelling of 161556365455 in words is "one hundred sixty-one billion, five hundred fifty-six million, three hundred sixty-five thousand, four hundred fifty-five".