161965897 has 2 divisors, whose sum is σ = 161965898. Its totient is φ = 161965896.

The previous prime is 161965873. The next prime is 161965939. The reversal of 161965897 is 798569161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 155226681 + 6739216 = 12459^2 + 2596^2 .

It is a cyclic number.

It is not a de Polignac number, because 161965897 - 2²⁷ = 27748169 is a prime.

It is not a weakly prime, because it can be changed into another prime (161968897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80982948 + 80982949.

It is an arithmetic number, because the mean of its divisors is an integer number (80982949).

Almost surely, 2^161965897 is an apocalyptic number.

It is an amenable number.

161965897 is a deficient number, since it is larger than the sum of its proper divisors (1).

161965897 is an equidigital number, since it uses as much as digits as its factorization.

161965897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 816480, while the sum is 52.

The square root of 161965897 is about 12726.5822984806. The cubic root of 161965897 is about 545.0979225333.

The spelling of 161965897 in words is "one hundred sixty-one million, nine hundred sixty-five thousand, eight hundred ninety-seven".