18047312261681 has 2 divisors, whose sum is σ = 18047312261682. Its totient is φ = 18047312261680.

The previous prime is 18047312261609. The next prime is 18047312261687. The reversal of 18047312261681 is 18616221374081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10582067554081 + 7465244707600 = 3253009^2 + 2732260^2 .

It is an emirp because it is prime and its reverse (18616221374081) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18047312261681 - 2³⁸ = 17772434354737 is a prime.

It is a super-2 number, since 2×18047312261681² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18047312261687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9023656130840 + 9023656130841.

It is an arithmetic number, because the mean of its divisors is an integer number (9023656130841).

Almost surely, 2^{18047312261681} is an apocalyptic number.

It is an amenable number.

18047312261681 is a deficient number, since it is larger than the sum of its proper divisors (1).

18047312261681 is an equidigital number, since it uses as much as digits as its factorization.

18047312261681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 774144, while the sum is 50.

The spelling of 18047312261681 in words is "eighteen trillion, forty-seven billion, three hundred twelve million, two hundred sixty-one thousand, six hundred eighty-one".