18963728209 has 2 divisors, whose sum is σ = 18963728210. Its totient is φ = 18963728208.

The previous prime is 18963728207. The next prime is 18963728263. The reversal of 18963728209 is 90282736981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13294090000 + 5669638209 = 115300^2 + 75297^2 .

It is a cyclic number.

It is not a de Polignac number, because 18963728209 - 2¹ = 18963728207 is a prime.

Together with 18963728207, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 18963728209.

It is not a weakly prime, because it can be changed into another prime (18963728207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9481864104 + 9481864105.

It is an arithmetic number, because the mean of its divisors is an integer number (9481864105).

Almost surely, 2^18963728209 is an apocalyptic number.

It is an amenable number.

18963728209 is a deficient number, since it is larger than the sum of its proper divisors (1).

18963728209 is an equidigital number, since it uses as much as digits as its factorization.

18963728209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2612736, while the sum is 55.

The spelling of 18963728209 in words is "eighteen billion, nine hundred sixty-three million, seven hundred twenty-eight thousand, two hundred nine".