18159899881 has 2 divisors, whose sum is σ = 18159899882. Its totient is φ = 18159899880.

The previous prime is 18159899869. The next prime is 18159899899. The reversal of 18159899881 is 18899895181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18036490000 + 123409881 = 134300^2 + 11109^2 .

It is an emirp because it is prime and its reverse (18899895181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18159899881 - 2⁹ = 18159899369 is a prime.

It is a super-2 number, since 2×18159899881² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18159899801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9079949940 + 9079949941.

It is an arithmetic number, because the mean of its divisors is an integer number (9079949941).

Almost surely, 2^18159899881 is an apocalyptic number.

It is an amenable number.

18159899881 is a deficient number, since it is larger than the sum of its proper divisors (1).

18159899881 is an equidigital number, since it uses as much as digits as its factorization.

18159899881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14929920, while the sum is 67.

The spelling of 18159899881 in words is "eighteen billion, one hundred fifty-nine million, eight hundred ninety-nine thousand, eight hundred eighty-one".