161959501897 has 2 divisors, whose sum is σ = 161959501898. Its totient is φ = 161959501896.

The previous prime is 161959501889. The next prime is 161959501901. The reversal of 161959501897 is 798105959161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81573643321 + 80385858576 = 285611^2 + 283524^2 .

It is a cyclic number.

It is not a de Polignac number, because 161959501897 - 2³ = 161959501889 is a prime.

It is not a weakly prime, because it can be changed into another prime (161959501807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80979750948 + 80979750949.

It is an arithmetic number, because the mean of its divisors is an integer number (80979750949).

Almost surely, 2^161959501897 is an apocalyptic number.

It is an amenable number.

161959501897 is a deficient number, since it is larger than the sum of its proper divisors (1).

161959501897 is an equidigital number, since it uses as much as digits as its factorization.

161959501897 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6123600, while the sum is 61.

The spelling of 161959501897 in words is "one hundred sixty-one billion, nine hundred fifty-nine million, five hundred one thousand, eight hundred ninety-seven".