18638992709 has 2 divisors, whose sum is σ = 18638992710. Its totient is φ = 18638992708.

The previous prime is 18638992703. The next prime is 18638992751. The reversal of 18638992709 is 90729983681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17836403809 + 802588900 = 133553^2 + 28330^2 .

It is a cyclic number.

It is not a de Polignac number, because 18638992709 - 2²⁰ = 18637944133 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18638992703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9319496354 + 9319496355.

It is an arithmetic number, because the mean of its divisors is an integer number (9319496355).

Almost surely, 2^18638992709 is an apocalyptic number.

It is an amenable number.

18638992709 is a deficient number, since it is larger than the sum of its proper divisors (1).

18638992709 is an equidigital number, since it uses as much as digits as its factorization.

18638992709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11757312, while the sum is 62.

The spelling of 18638992709 in words is "eighteen billion, six hundred thirty-eight million, nine hundred ninety-two thousand, seven hundred nine".