18683210621 has 2 divisors, whose sum is σ = 18683210622. Its totient is φ = 18683210620.

The previous prime is 18683210597. The next prime is 18683210627. The reversal of 18683210621 is 12601238681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9825765625 + 8857444996 = 99125^2 + 94114^2 .

It is an emirp because it is prime and its reverse (12601238681) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18683210621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18683210627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9341605310 + 9341605311.

It is an arithmetic number, because the mean of its divisors is an integer number (9341605311).

Almost surely, 2^18683210621 is an apocalyptic number.

It is an amenable number.

18683210621 is a deficient number, since it is larger than the sum of its proper divisors (1).

18683210621 is an equidigital number, since it uses as much as digits as its factorization.

18683210621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27648, while the sum is 38.

The spelling of 18683210621 in words is "eighteen billion, six hundred eighty-three million, two hundred ten thousand, six hundred twenty-one".