18561681679 has 2 divisors, whose sum is σ = 18561681680. Its totient is φ = 18561681678.

The previous prime is 18561681667. The next prime is 18561681689. The reversal of 18561681679 is 97618616581.

It is a strong prime.

It is an emirp because it is prime and its reverse (97618616581) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18561681679 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18561681629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9280840839 + 9280840840.

It is an arithmetic number, because the mean of its divisors is an integer number (9280840840).

Almost surely, 2^18561681679 is an apocalyptic number.

18561681679 is a deficient number, since it is larger than the sum of its proper divisors (1).

18561681679 is an equidigital number, since it uses as much as digits as its factorization.

18561681679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4354560, while the sum is 58.

The spelling of 18561681679 in words is "eighteen billion, five hundred sixty-one million, six hundred eighty-one thousand, six hundred seventy-nine".