18993479 has 4 divisors (see below), whose sum is σ = 19015920. Its totient is φ = 18971040.

The previous prime is 18993449. The next prime is 18993493. The reversal of 18993479 is 97439981.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18993479 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 (18993419) 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 3 ways as a sum of consecutive naturals, for example, 9899 + ... + 11660.

It is an arithmetic number, because the mean of its divisors is an integer number (4753980).

Almost surely, 2^18993479 is an apocalyptic number.

18993479 is a deficient number, since it is larger than the sum of its proper divisors (22441).

18993479 is an equidigital number, since it uses as much as digits as its factorization.

18993479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22440.

The product of its digits is 489888, while the sum is 50.

The square root of 18993479 is about 4358.1508693481. The cubic root of 18993479 is about 266.8096339279.

The spelling of 18993479 in words is "eighteen million, nine hundred ninety-three thousand, four hundred seventy-nine".