18812993 has 2 divisors, whose sum is σ = 18812994. Its totient is φ = 18812992.

The previous prime is 18812987. The next prime is 18813007. The reversal of 18812993 is 39921881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14047504 + 4765489 = 3748^2 + 2183^2 .

It is an emirp because it is prime and its reverse (39921881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18812993 - 2⁶ = 18812929 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18812993.

It is not a weakly prime, because it can be changed into another prime (18812953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9406496 + 9406497.

It is an arithmetic number, because the mean of its divisors is an integer number (9406497).

Almost surely, 2^18812993 is an apocalyptic number.

It is an amenable number.

18812993 is a deficient number, since it is larger than the sum of its proper divisors (1).

18812993 is an equidigital number, since it uses as much as digits as its factorization.

18812993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 41.

The square root of 18812993 is about 4337.3947249472. The cubic root of 18812993 is about 265.9618210793.

The spelling of 18812993 in words is "eighteen million, eight hundred twelve thousand, nine hundred ninety-three".