18218493 has 8 divisors (see below), whose sum is σ = 26990400. Its totient is φ = 12145644.

The previous prime is 18218491. The next prime is 18218513. The reversal of 18218493 is 39481281.

It is not a de Polignac number, because 18218493 - 2¹ = 18218491 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18218491) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 337353 + ... + 337406.

It is an arithmetic number, because the mean of its divisors is an integer number (3373800).

Almost surely, 2^18218493 is an apocalyptic number.

It is an amenable number.

18218493 is a deficient number, since it is larger than the sum of its proper divisors (8771907).

18218493 is an equidigital number, since it uses as much as digits as its factorization.

18218493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 674768 (or 674762 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 18218493 is about 4268.3126642738. The cubic root of 18218493 is about 263.1302732321.

The spelling of 18218493 in words is "eighteen million, two hundred eighteen thousand, four hundred ninety-three".