18998657281 has 2 divisors, whose sum is σ = 18998657282. Its totient is φ = 18998657280.

The previous prime is 18998657269. The next prime is 18998657287. The reversal of 18998657281 is 18275689981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13131097281 + 5867560000 = 114591^2 + 76600^2 .

It is an emirp because it is prime and its reverse (18275689981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18998657281 - 2³³ = 10408722689 is a prime.

It is a super-2 number, since 2×18998657281² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18998657287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9499328640 + 9499328641.

It is an arithmetic number, because the mean of its divisors is an integer number (9499328641).

Almost surely, 2^18998657281 is an apocalyptic number.

It is an amenable number.

18998657281 is a deficient number, since it is larger than the sum of its proper divisors (1).

18998657281 is an equidigital number, since it uses as much as digits as its factorization.

18998657281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17418240, while the sum is 64.

The spelling of 18998657281 in words is "eighteen billion, nine hundred ninety-eight million, six hundred fifty-seven thousand, two hundred eighty-one".