161664961 has 2 divisors, whose sum is σ = 161664962. Its totient is φ = 161664960.

The previous prime is 161664959. The next prime is 161664967. The reversal of 161664961 is 169466161.

161664961 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 152399025 + 9265936 = 12345^2 + 3044^2 .

It is a cyclic number.

It is not a de Polignac number, because 161664961 - 2¹ = 161664959 is a prime.

It is a super-2 number, since 2×161664961² = 52271119230263042, which contains 22 as substring.

Together with 161664959, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (161664967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80832480 + 80832481.

It is an arithmetic number, because the mean of its divisors is an integer number (80832481).

Almost surely, 2^161664961 is an apocalyptic number.

It is an amenable number.

161664961 is a deficient number, since it is larger than the sum of its proper divisors (1).

161664961 is an equidigital number, since it uses as much as digits as its factorization.

161664961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46656, while the sum is 40.

The square root of 161664961 is about 12714.7536743737. The cubic root of 161664961 is about 544.7601121407.

The spelling of 161664961 in words is "one hundred sixty-one million, six hundred sixty-four thousand, nine hundred sixty-one".