18618993 has 12 divisors (see below), whose sum is σ = 28309840. Its totient is φ = 11759256.

The previous prime is 18618991. The next prime is 18619009. The reversal of 18618993 is 39981681.

It is not a de Polignac number, because 18618993 - 2¹ = 18618991 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18618991) 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 in 11 ways as a sum of consecutive naturals, for example, 54271 + ... + 54612.

Almost surely, 2^18618993 is an apocalyptic number.

It is an amenable number.

18618993 is a deficient number, since it is larger than the sum of its proper divisors (9690847).

18618993 is a wasteful number, since it uses less digits than its factorization.

18618993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108908 (or 108905 counting only the distinct ones).

The product of its digits is 93312, while the sum is 45.

The square root of 18618993 is about 4314.9731169499. The cubic root of 18618993 is about 265.0444591361.

The spelling of 18618993 in words is "eighteen million, six hundred eighteen thousand, nine hundred ninety-three".