18708485921 has 2 divisors, whose sum is σ = 18708485922. Its totient is φ = 18708485920.

The previous prime is 18708485897. The next prime is 18708485969. The reversal of 18708485921 is 12958480781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13187995921 + 5520490000 = 114839^2 + 74300^2 .

It is a cyclic number.

It is not a de Polignac number, because 18708485921 - 2¹⁰ = 18708484897 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (18707485921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9354242960 + 9354242961.

It is an arithmetic number, because the mean of its divisors is an integer number (9354242961).

Almost surely, 2^18708485921 is an apocalyptic number.

It is an amenable number.

18708485921 is a deficient number, since it is larger than the sum of its proper divisors (1).

18708485921 is an equidigital number, since it uses as much as digits as its factorization.

18708485921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1290240, while the sum is 53.

The spelling of 18708485921 in words is "eighteen billion, seven hundred eight million, four hundred eighty-five thousand, nine hundred twenty-one".