161890973 has 2 divisors, whose sum is σ = 161890974. Its totient is φ = 161890972.

The previous prime is 161890931. The next prime is 161891003. The reversal of 161890973 is 379098161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 147428164 + 14462809 = 12142^2 + 3803^2 .

It is a cyclic number.

It is not a de Polignac number, because 161890973 - 2¹⁸ = 161628829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161890903) 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, 80945486 + 80945487.

It is an arithmetic number, because the mean of its divisors is an integer number (80945487).

Almost surely, 2^161890973 is an apocalyptic number.

It is an amenable number.

161890973 is a deficient number, since it is larger than the sum of its proper divisors (1).

161890973 is an equidigital number, since it uses as much as digits as its factorization.

161890973 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81648, while the sum is 44.

The square root of 161890973 is about 12723.6383554391. The cubic root of 161890973 is about 545.0138570671.

The spelling of 161890973 in words is "one hundred sixty-one million, eight hundred ninety thousand, nine hundred seventy-three".