161518631 has 2 divisors, whose sum is σ = 161518632. Its totient is φ = 161518630.

The previous prime is 161518619. The next prime is 161518657. The reversal of 161518631 is 136815161.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161518631 is a prime.

It is a super-2 number, since 2×161518631² = 52176536320228322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161518531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80759315 + 80759316.

It is an arithmetic number, because the mean of its divisors is an integer number (80759316).

Almost surely, 2^161518631 is an apocalyptic number.

161518631 is a deficient number, since it is larger than the sum of its proper divisors (1).

161518631 is an equidigital number, since it uses as much as digits as its factorization.

161518631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 32.

The square root of 161518631 is about 12708.9980328899. The cubic root of 161518631 is about 544.5957004877.

The spelling of 161518631 in words is "one hundred sixty-one million, five hundred eighteen thousand, six hundred thirty-one".