18738993 has 32 divisors (see below), whose sum is σ = 31159296. Its totient is φ = 9753408.

The previous prime is 18738991. The next prime is 18739003. The reversal of 18738993 is 39983781.

It is not a de Polignac number, because 18738993 - 2¹ = 18738991 is a prime.

It is a super-2 number, since 2×18738993² = 702299717308098, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18738991) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22246 + ... + 23072.

It is an arithmetic number, because the mean of its divisors is an integer number (973728).

Almost surely, 2^18738993 is an apocalyptic number.

18738993 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

18738993 is a deficient number, since it is larger than the sum of its proper divisors (12420303).

18738993 is a wasteful number, since it uses less digits than its factorization.

18738993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 933.

The product of its digits is 326592, while the sum is 48.

The square root of 18738993 is about 4328.8558534560. The cubic root of 18738993 is about 265.6126468627.

The spelling of 18738993 in words is "eighteen million, seven hundred thirty-eight thousand, nine hundred ninety-three".