18520493 has 2 divisors, whose sum is σ = 18520494. Its totient is φ = 18520492.

The previous prime is 18520477. The next prime is 18520553. The reversal of 18520493 is 39402581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16662724 + 1857769 = 4082^2 + 1363^2 .

It is a cyclic number.

It is not a de Polignac number, because 18520493 - 2⁴ = 18520477 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18520693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9260246 + 9260247.

It is an arithmetic number, because the mean of its divisors is an integer number (9260247).

Almost surely, 2^18520493 is an apocalyptic number.

It is an amenable number.

18520493 is a deficient number, since it is larger than the sum of its proper divisors (1).

18520493 is an equidigital number, since it uses as much as digits as its factorization.

18520493 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 18520493 is about 4303.5442370214. The cubic root of 18520493 is about 264.5762445425.

The spelling of 18520493 in words is "eighteen million, five hundred twenty thousand, four hundred ninety-three".