18647365993 has 2 divisors, whose sum is σ = 18647365994. Its totient is φ = 18647365992.

The previous prime is 18647365981. The next prime is 18647366021. The reversal of 18647365993 is 39956374681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17796360409 + 851005584 = 133403^2 + 29172^2 .

It is an emirp because it is prime and its reverse (39956374681) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18647365993 is a prime.

It is not a weakly prime, because it can be changed into another prime (18647365193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9323682996 + 9323682997.

It is an arithmetic number, because the mean of its divisors is an integer number (9323682997).

Almost surely, 2^18647365993 is an apocalyptic number.

It is an amenable number.

18647365993 is a deficient number, since it is larger than the sum of its proper divisors (1).

18647365993 is an equidigital number, since it uses as much as digits as its factorization.

18647365993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 29393280, while the sum is 61.

The spelling of 18647365993 in words is "eighteen billion, six hundred forty-seven million, three hundred sixty-five thousand, nine hundred ninety-three".