161805680 has 40 divisors (see below), whose sum is σ = 385381584. Its totient is φ = 63142400.

The previous prime is 161805673. The next prime is 161805697. The reversal of 161805680 is 86508161.

161805680 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 161805680.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21386 + ... + 27945.

Almost surely, 2^161805680 is an apocalyptic number.

161805680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161805680 is an abundant number, since it is smaller than the sum of its proper divisors (223575904).

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

161805680 is a wasteful number, since it uses less digits than its factorization.

161805680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49385 (or 49379 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 35.

The square root of 161805680 is about 12720.2861603032. The cubic root of 161805680 is about 544.9181259047.

The spelling of 161805680 in words is "one hundred sixty-one million, eight hundred five thousand, six hundred eighty".