161665555600 has 60 divisors (see below), whose sum is σ = 405288542016. Its totient is φ = 61854643840.

The previous prime is 161665555559. The next prime is 161665555619. The reversal of 161665555600 is 6555566161.

It is a super-2 number, since 2×161665555600² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8776972 + ... + 8795371.

Almost surely, 2^161665555600 is an apocalyptic number.

161665555600 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161665555600 is an abundant number, since it is smaller than the sum of its proper divisors (243622986416).

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

161665555600 is a wasteful number, since it uses less digits than its factorization.

161665555600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17572384 (or 17572373 counting only the distinct ones).

The product of its (nonzero) digits is 810000, while the sum is 46.

The spelling of 161665555600 in words is "one hundred sixty-one billion, six hundred sixty-five million, five hundred fifty-five thousand, six hundred".