161605566661600 has 72 divisors (see below), whose sum is σ = 395240833077048. Its totient is φ = 64524050572800.

The previous prime is 161605566661549. The next prime is 161605566661619. The reversal of 161605566661600 is 6166665506161.

It is a super-2 number, since 2×161605566661600² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 184212271 + ... + 185087470.

It is an arithmetic number, because the mean of its divisors is an integer number (5489456014959).

Almost surely, 2^{161605566661600} is an apocalyptic number.

161605566661600 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161605566661600 is an abundant number, since it is smaller than the sum of its proper divisors (233635266415448).

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

161605566661600 is a wasteful number, since it uses less digits than its factorization.

161605566661600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 369300308 (or 369300295 counting only the distinct ones).

The product of its (nonzero) digits is 6998400, while the sum is 55.

The spelling of 161605566661600 in words is "one hundred sixty-one trillion, six hundred five billion, five hundred sixty-six million, six hundred sixty-one thousand, six hundred".