161884909517 has 2 divisors, whose sum is σ = 161884909518. Its totient is φ = 161884909516.

The previous prime is 161884909489. The next prime is 161884909583. The reversal of 161884909517 is 715909488161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 118175062756 + 43709846761 = 343766^2 + 209069^2 .

It is a cyclic number.

It is not a de Polignac number, because 161884909517 - 2¹⁸ = 161884647373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161884900517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80942454758 + 80942454759.

It is an arithmetic number, because the mean of its divisors is an integer number (80942454759).

Almost surely, 2^161884909517 is an apocalyptic number.

It is an amenable number.

161884909517 is a deficient number, since it is larger than the sum of its proper divisors (1).

161884909517 is an equidigital number, since it uses as much as digits as its factorization.

161884909517 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4354560, while the sum is 59.

The spelling of 161884909517 in words is "one hundred sixty-one billion, eight hundred eighty-four million, nine hundred nine thousand, five hundred seventeen".