18821824993 has 2 divisors, whose sum is σ = 18821824994. Its totient is φ = 18821824992.

The previous prime is 18821824979. The next prime is 18821825039. The reversal of 18821824993 is 39942812881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15867685089 + 2954139904 = 125967^2 + 54352^2 .

It is a cyclic number.

It is not a de Polignac number, because 18821824993 - 2⁹ = 18821824481 is a prime.

It is a super-2 number, since 2×18821824993² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18821825993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9410912496 + 9410912497.

It is an arithmetic number, because the mean of its divisors is an integer number (9410912497).

Almost surely, 2^18821824993 is an apocalyptic number.

It is an amenable number.

18821824993 is a deficient number, since it is larger than the sum of its proper divisors (1).

18821824993 is an equidigital number, since it uses as much as digits as its factorization.

18821824993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1990656, while the sum is 55.

The spelling of 18821824993 in words is "eighteen billion, eight hundred twenty-one million, eight hundred twenty-four thousand, nine hundred ninety-three".