161798531 has 2 divisors, whose sum is σ = 161798532. Its totient is φ = 161798530.

The previous prime is 161798519. The next prime is 161798561. The reversal of 161798531 is 135897161.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 161798531 - 2¹⁰ = 161797507 is a prime.

It is a super-2 number, since 2×161798531² = 52357529267515922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (161798561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80899265 + 80899266.

It is an arithmetic number, because the mean of its divisors is an integer number (80899266).

Almost surely, 2^161798531 is an apocalyptic number.

161798531 is a deficient number, since it is larger than the sum of its proper divisors (1).

161798531 is an equidigital number, since it uses as much as digits as its factorization.

161798531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45360, while the sum is 41.

The square root of 161798531 is about 12720.0051493700. The cubic root of 161798531 is about 544.9101004818.

The spelling of 161798531 in words is "one hundred sixty-one million, seven hundred ninety-eight thousand, five hundred thirty-one".