161619666889 has 2 divisors, whose sum is σ = 161619666890. Its totient is φ = 161619666888.

The previous prime is 161619666863. The next prime is 161619666941. The reversal of 161619666889 is 988666916161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121248811264 + 40370855625 = 348208^2 + 200925^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161619666889 is a prime.

It is a super-2 number, since 2×161619666889² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (161619666839) 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, 80809833444 + 80809833445.

It is an arithmetic number, because the mean of its divisors is an integer number (80809833445).

Almost surely, 2^161619666889 is an apocalyptic number.

It is an amenable number.

161619666889 is a deficient number, since it is larger than the sum of its proper divisors (1).

161619666889 is an equidigital number, since it uses as much as digits as its factorization.

161619666889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40310784, while the sum is 67.

The spelling of 161619666889 in words is "one hundred sixty-one billion, six hundred nineteen million, six hundred sixty-six thousand, eight hundred eighty-nine".