18904639 has 8 divisors (see below), whose sum is σ = 21430640. Its totient is φ = 16531776.

The previous prime is 18904583. The next prime is 18904679. The reversal of 18904639 is 93640981.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18904639 - 2¹³ = 18896447 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 (18904679) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38022 + ... + 38515.

It is an arithmetic number, because the mean of its divisors is an integer number (2678830).

Almost surely, 2^18904639 is an apocalyptic number.

18904639 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

18904639 is a deficient number, since it is larger than the sum of its proper divisors (2526001).

18904639 is a wasteful number, since it uses less digits than its factorization.

18904639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76569.

The product of its (nonzero) digits is 46656, while the sum is 40.

The square root of 18904639 is about 4347.9465268101. The cubic root of 18904639 is about 266.3929923202.

The spelling of 18904639 in words is "eighteen million, nine hundred four thousand, six hundred thirty-nine".