161369391 has 4 divisors (see below), whose sum is σ = 215159192. Its totient is φ = 107579592.

The previous prime is 161369381. The next prime is 161369393. The reversal of 161369391 is 193963161.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 161369391 - 2¹⁰ = 161368367 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161369393) 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, 26894896 + ... + 26894901.

It is an arithmetic number, because the mean of its divisors is an integer number (53789798).

Almost surely, 2^161369391 is an apocalyptic number.

161369391 is a deficient number, since it is larger than the sum of its proper divisors (53789801).

161369391 is an equidigital number, since it uses as much as digits as its factorization.

161369391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53789800.

The product of its digits is 26244, while the sum is 39.

The square root of 161369391 is about 12703.1252453875. The cubic root of 161369391 is about 544.4279169385.

The spelling of 161369391 in words is "one hundred sixty-one million, three hundred sixty-nine thousand, three hundred ninety-one".