161668961 has 2 divisors, whose sum is σ = 161668962. Its totient is φ = 161668960.

The previous prime is 161668931. The next prime is 161668973. The reversal of 161668961 is 169866161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 115971361 + 45697600 = 10769^2 + 6760^2 .

It is an emirp because it is prime and its reverse (169866161) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 196899191 and 191998691.

It is a cyclic number.

It is not a de Polignac number, because 161668961 - 2¹⁰ = 161667937 is a prime.

It is a super-2 number, since 2×161668961² = 52273705901639042, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (161668931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80834480 + 80834481.

It is an arithmetic number, because the mean of its divisors is an integer number (80834481).

Almost surely, 2^161668961 is an apocalyptic number.

It is an amenable number.

161668961 is a deficient number, since it is larger than the sum of its proper divisors (1).

161668961 is an equidigital number, since it uses as much as digits as its factorization.

161668961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 93312, while the sum is 44.

The square root of 161668961 is about 12714.9109709821. The cubic root of 161668961 is about 544.7646050180.

The spelling of 161668961 in words is "one hundred sixty-one million, six hundred sixty-eight thousand, nine hundred sixty-one".