18924391 has 4 divisors (see below), whose sum is σ = 19068984. Its totient is φ = 18779800.

The previous prime is 18924359. The next prime is 18924403. The reversal of 18924391 is 19342981.

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

It is a cyclic number.

It is not a de Polignac number, because 18924391 - 2⁵ = 18924359 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18924391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18922391) 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, 72100 + ... + 72361.

It is an arithmetic number, because the mean of its divisors is an integer number (4767246).

Almost surely, 2^18924391 is an apocalyptic number.

18924391 is a deficient number, since it is larger than the sum of its proper divisors (144593).

18924391 is a wasteful number, since it uses less digits than its factorization.

18924391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144592.

The product of its digits is 15552, while the sum is 37.

The square root of 18924391 is about 4350.2173508918. The cubic root of 18924391 is about 266.4857378609.

The spelling of 18924391 in words is "eighteen million, nine hundred twenty-four thousand, three hundred ninety-one".