18022493 has 4 divisors (see below), whose sum is σ = 18462108. Its totient is φ = 17582880.

The previous prime is 18022489. The next prime is 18022513. The reversal of 18022493 is 39422081.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10936249 + 7086244 = 3307^2 + 2662^2 .

It is a cyclic number.

It is not a de Polignac number, because 18022493 - 2² = 18022489 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18022453) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 219746 + ... + 219827.

It is an arithmetic number, because the mean of its divisors is an integer number (4615527).

Almost surely, 2^18022493 is an apocalyptic number.

It is an amenable number.

18022493 is a deficient number, since it is larger than the sum of its proper divisors (439615).

18022493 is an equidigital number, since it uses as much as digits as its factorization.

18022493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439614.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 18022493 is about 4245.2906849826. The cubic root of 18022493 is about 262.1832575673.

The spelling of 18022493 in words is "eighteen million, twenty-two thousand, four hundred ninety-three".