18005997481 has 2 divisors, whose sum is σ = 18005997482. Its totient is φ = 18005997480.

The previous prime is 18005997439. The next prime is 18005997487. The reversal of 18005997481 is 18479950081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15925178025 + 2080819456 = 126195^2 + 45616^2 .

It is an emirp because it is prime and its reverse (18479950081) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18005997481 is a prime.

It is a super-2 number, since 2×18005997481² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18005997487) 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, 9002998740 + 9002998741.

It is an arithmetic number, because the mean of its divisors is an integer number (9002998741).

Almost surely, 2^18005997481 is an apocalyptic number.

It is an amenable number.

18005997481 is a deficient number, since it is larger than the sum of its proper divisors (1).

18005997481 is an equidigital number, since it uses as much as digits as its factorization.

18005997481 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 725760, while the sum is 52.

The spelling of 18005997481 in words is "eighteen billion, five million, nine hundred ninety-seven thousand, four hundred eighty-one".