161311280 has 80 divisors (see below), whose sum is σ = 407890560. Its totient is φ = 58973184.

The previous prime is 161311279. The next prime is 161311301. The reversal of 161311280 is 82113161.

It is a tau number, because it is divible by the number of its divisors (80).

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 15 ways as a sum of consecutive naturals, for example, 112649 + ... + 114071.

It is an arithmetic number, because the mean of its divisors is an integer number (5098632).

Almost surely, 2^161311280 is an apocalyptic number.

161311280 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161311280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (203945280).

161311280 is an abundant number, since it is smaller than the sum of its proper divisors (246579280).

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

161311280 is a wasteful number, since it uses less digits than its factorization.

161311280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1558 (or 1552 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 161311280 is about 12700.8377676435. The cubic root of 161311280 is about 544.3625574779.

The spelling of 161311280 in words is "one hundred sixty-one million, three hundred eleven thousand, two hundred eighty".