161858195431 has 2 divisors, whose sum is σ = 161858195432. Its totient is φ = 161858195430.

The previous prime is 161858195351. The next prime is 161858195459. The reversal of 161858195431 is 134591858161.

It is a strong prime.

It is an emirp because it is prime and its reverse (134591858161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161858195431 - 2²³ = 161849806823 is a prime.

It is a super-2 number, since 2×161858195431² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161858195231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80929097715 + 80929097716.

It is an arithmetic number, because the mean of its divisors is an integer number (80929097716).

Almost surely, 2^161858195431 is an apocalyptic number.

161858195431 is a deficient number, since it is larger than the sum of its proper divisors (1).

161858195431 is an equidigital number, since it uses as much as digits as its factorization.

161858195431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1036800, while the sum is 52.

The spelling of 161858195431 in words is "one hundred sixty-one billion, eight hundred fifty-eight million, one hundred ninety-five thousand, four hundred thirty-one".