18939628489 has 2 divisors, whose sum is σ = 18939628490. Its totient is φ = 18939628488.

The previous prime is 18939628451. The next prime is 18939628517. The reversal of 18939628489 is 98482693981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18849093264 + 90535225 = 137292^2 + 9515^2 .

It is a cyclic number.

It is not a de Polignac number, because 18939628489 - 2²³ = 18931239881 is a prime.

It is not a weakly prime, because it can be changed into another prime (18939628289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9469814244 + 9469814245.

It is an arithmetic number, because the mean of its divisors is an integer number (9469814245).

Almost surely, 2^18939628489 is an apocalyptic number.

It is an amenable number.

18939628489 is a deficient number, since it is larger than the sum of its proper divisors (1).

18939628489 is an equidigital number, since it uses as much as digits as its factorization.

18939628489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 53747712, while the sum is 67.

The spelling of 18939628489 in words is "eighteen billion, nine hundred thirty-nine million, six hundred twenty-eight thousand, four hundred eighty-nine".