161957797 has 2 divisors, whose sum is σ = 161957798. Its totient is φ = 161957796.

The previous prime is 161957791. The next prime is 161957833. The reversal of 161957797 is 797759161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 161823841 + 133956 = 12721^2 + 366^2 .

It is an emirp because it is prime and its reverse (797759161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161957797 - 2⁷ = 161957669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161957791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80978898 + 80978899.

It is an arithmetic number, because the mean of its divisors is an integer number (80978899).

Almost surely, 2^161957797 is an apocalyptic number.

It is an amenable number.

161957797 is a deficient number, since it is larger than the sum of its proper divisors (1).

161957797 is an equidigital number, since it uses as much as digits as its factorization.

161957797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 833490, while the sum is 52.

The square root of 161957797 is about 12726.2640629526. The cubic root of 161957797 is about 545.0888355035.

The spelling of 161957797 in words is "one hundred sixty-one million, nine hundred fifty-seven thousand, seven hundred ninety-seven".