161665656580 has 48 divisors (see below), whose sum is σ = 350696586240. Its totient is φ = 62536118400.

The previous prime is 161665656557. The next prime is 161665656583. The reversal of 161665656580 is 85656566161.

It is a super-2 number, since 2×161665656580² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161665656583) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 794745 + ... + 977215.

It is an arithmetic number, because the mean of its divisors is an integer number (7306178880).

Almost surely, 2^161665656580 is an apocalyptic number.

161665656580 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161665656580 is an abundant number, since it is smaller than the sum of its proper divisors (189030929660).

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

161665656580 is a wasteful number, since it uses less digits than its factorization.

161665656580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183940 (or 183938 counting only the distinct ones).

The product of its (nonzero) digits is 7776000, while the sum is 55.

The spelling of 161665656580 in words is "one hundred sixty-one billion, six hundred sixty-five million, six hundred fifty-six thousand, five hundred eighty".