161937561555 has 360 divisors, whose sum is σ = 393103839744. Its totient is φ = 63324011520.

The previous prime is 161937561479. The next prime is 161937561619. The reversal of 161937561555 is 555165739161.

161937561555 is a `hidden beast` number, since 1 + 6 + 1 + 9 + 37 + 56 + 1 + 555 = 666.

It is not a de Polignac number, because 161937561555 - 2⁷ = 161937561427 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 359 ways as a sum of consecutive naturals, for example, 40819182 + ... + 40823148.

Almost surely, 2^161937561555 is an apocalyptic number.

161937561555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

161937561555 is an abundant number, since it is smaller than the sum of its proper divisors (231166278189).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161937561555 is a wasteful number, since it uses less digits than its factorization.

161937561555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4037 (or 4010 counting only the distinct ones).

The product of its digits is 4252500, while the sum is 54.

The spelling of 161937561555 in words is "one hundred sixty-one billion, nine hundred thirty-seven million, five hundred sixty-one thousand, five hundred fifty-five".