165663332460581 has 2 divisors, whose sum is σ = 165663332460582. Its totient is φ = 165663332460580.

The previous prime is 165663332460541. The next prime is 165663332460673. The reversal of 165663332460581 is 185064233366561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 133267029809956 + 32396302650625 = 11544134^2 + 5691775^2 .

It is a cyclic number.

It is not a de Polignac number, because 165663332460581 - 2¹⁸ = 165663332198437 is a prime.

It is a super-2 number, since 2×165663332460581² (a number of 29 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 165663332460581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165663332460541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82831666230290 + 82831666230291.

It is an arithmetic number, because the mean of its divisors is an integer number (82831666230291).

Almost surely, 2^{165663332460581} is an apocalyptic number.

It is an amenable number.

165663332460581 is a deficient number, since it is larger than the sum of its proper divisors (1).

165663332460581 is an equidigital number, since it uses as much as digits as its factorization.

165663332460581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 55987200, while the sum is 59.

The spelling of 165663332460581 in words is "one hundred sixty-five trillion, six hundred sixty-three billion, three hundred thirty-two million, four hundred sixty thousand, five hundred eighty-one".