161791780 has 24 divisors (see below), whose sum is σ = 341095608. Its totient is φ = 64462848.

The previous prime is 161791741. The next prime is 161791823. The reversal of 161791780 is 87197161.

161791780 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 72829156 + 88962624 = 8534^2 + 9432^2 .

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, 10599 + ... + 20878.

It is an arithmetic number, because the mean of its divisors is an integer number (14212317).

Almost surely, 2^161791780 is an apocalyptic number.

161791780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161791780 is an abundant number, since it is smaller than the sum of its proper divisors (179303828).

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

161791780 is a wasteful number, since it uses less digits than its factorization.

161791780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31743 (or 31741 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 40.

The square root of 161791780 is about 12719.7397772124. The cubic root of 161791780 is about 544.9025216341.

The spelling of 161791780 in words is "one hundred sixty-one million, seven hundred ninety-one thousand, seven hundred eighty".