161313891 has 4 divisors (see below), whose sum is σ = 215085192. Its totient is φ = 107542592.

The previous prime is 161313883. The next prime is 161313913. The reversal of 161313891 is 198313161.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 198313161 = 3 ⋅66104387.

It is a cyclic number.

It is not a de Polignac number, because 161313891 - 2³ = 161313883 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161313851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26885646 + ... + 26885651.

It is an arithmetic number, because the mean of its divisors is an integer number (53771298).

Almost surely, 2^161313891 is an apocalyptic number.

161313891 is a deficient number, since it is larger than the sum of its proper divisors (53771301).

161313891 is an equidigital number, since it uses as much as digits as its factorization.

161313891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53771300.

The product of its digits is 3888, while the sum is 33.

The square root of 161313891 is about 12700.9405557226. The cubic root of 161313891 is about 544.3654944971.

The spelling of 161313891 in words is "one hundred sixty-one million, three hundred thirteen thousand, eight hundred ninety-one".