161163891 has 48 divisors (see below), whose sum is σ = 282437280. Its totient is φ = 90538560.

The previous prime is 161163887. The next prime is 161163911. The reversal of 161163891 is 198361161.

It is a happy number.

161163891 is a `hidden beast` number, since 1 + 6 + 11 + 638 + 9 + 1 = 666.

It is not a de Polignac number, because 161163891 - 2² = 161163887 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161163811) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 79705 + ... + 81701.

It is an arithmetic number, because the mean of its divisors is an integer number (5884110).

Almost surely, 2^161163891 is an apocalyptic number.

161163891 is a deficient number, since it is larger than the sum of its proper divisors (121273389).

161163891 is a wasteful number, since it uses less digits than its factorization.

161163891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2081 (or 2068 counting only the distinct ones).

The product of its digits is 7776, while the sum is 36.

The square root of 161163891 is about 12695.0341078707. The cubic root of 161163891 is about 544.1967135238.

The spelling of 161163891 in words is "one hundred sixty-one million, one hundred sixty-three thousand, eight hundred ninety-one".