18280993 has 2 divisors, whose sum is σ = 18280994. Its totient is φ = 18280992.

The previous prime is 18280981. The next prime is 18281023. The reversal of 18280993 is 39908281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16916769 + 1364224 = 4113^2 + 1168^2 .

It is a cyclic number.

It is not a de Polignac number, because 18280993 - 2⁵ = 18280961 is a prime.

It is not a weakly prime, because it can be changed into another prime (18280903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9140496 + 9140497.

It is an arithmetic number, because the mean of its divisors is an integer number (9140497).

Almost surely, 2^18280993 is an apocalyptic number.

It is an amenable number.

18280993 is a deficient number, since it is larger than the sum of its proper divisors (1).

18280993 is an equidigital number, since it uses as much as digits as its factorization.

18280993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 18280993 is about 4275.6277901613. The cubic root of 18280993 is about 263.4308262985.

The spelling of 18280993 in words is "eighteen million, two hundred eighty thousand, nine hundred ninety-three".