163544594861581 has 2 divisors, whose sum is σ = 163544594861582. Its totient is φ = 163544594861580.

The previous prime is 163544594861573. The next prime is 163544594861603. The reversal of 163544594861581 is 185168495445361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 117420326356356 + 46124268505225 = 10836066^2 + 6791485^2 .

It is a cyclic number.

It is not a de Polignac number, because 163544594861581 - 2³ = 163544594861573 is a prime.

It is a super-2 number, since 2×163544594861581² (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 163544594861581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (163544594861561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 81772297430790 + 81772297430791.

It is an arithmetic number, because the mean of its divisors is an integer number (81772297430791).

Almost surely, 2^{163544594861581} is an apocalyptic number.

It is an amenable number.

163544594861581 is a deficient number, since it is larger than the sum of its proper divisors (1).

163544594861581 is an equidigital number, since it uses as much as digits as its factorization.

163544594861581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 497664000, while the sum is 70.

The spelling of 163544594861581 in words is "one hundred sixty-three trillion, five hundred forty-four billion, five hundred ninety-four million, eight hundred sixty-one thousand, five hundred eighty-one".