18981618864613 has 2 divisors, whose sum is σ = 18981618864614. Its totient is φ = 18981618864612.

The previous prime is 18981618864589. The next prime is 18981618864641. The reversal of 18981618864613 is 31646881618981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14449288693284 + 4532330171329 = 3801222^2 + 2128927^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18981618864613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18981618864913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9490809432306 + 9490809432307.

It is an arithmetic number, because the mean of its divisors is an integer number (9490809432307).

Almost surely, 2^{18981618864613} is an apocalyptic number.

It is an amenable number.

18981618864613 is a deficient number, since it is larger than the sum of its proper divisors (1).

18981618864613 is an equidigital number, since it uses as much as digits as its factorization.

18981618864613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 95551488, while the sum is 70.

The spelling of 18981618864613 in words is "eighteen trillion, nine hundred eighty-one billion, six hundred eighteen million, eight hundred sixty-four thousand, six hundred thirteen".