161619191 has 2 divisors, whose sum is σ = 161619192. Its totient is φ = 161619190.

The previous prime is 161619181. The next prime is 161619193. The reversal of 161619191 is 191916161.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (191916161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161619191 - 2²² = 157424887 is a prime.

It is a super-2 number, since 2×161619191² = 52241525798988962, which contains 22 as substring.

Together with 161619193, it forms a pair of twin primes.

It is a Chen prime.

161619191 is a strobogrammatic number because it is the same when read upside-down.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161619193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80809595 + 80809596.

It is an arithmetic number, because the mean of its divisors is an integer number (80809596).

Almost surely, 2^161619191 is an apocalyptic number.

161619191 is a deficient number, since it is larger than the sum of its proper divisors (1).

161619191 is an equidigital number, since it uses as much as digits as its factorization.

161619191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2916, while the sum is 35.

The square root of 161619191 is about 12712.9536693878. The cubic root of 161619191 is about 544.7086971163.

It can be divided in two parts, 16161 and 9191, that added together give a palindrome (25352).

The spelling of 161619191 in words is "one hundred sixty-one million, six hundred nineteen thousand, one hundred ninety-one".