18493891 has 8 divisors (see below), whose sum is σ = 19958400. Its totient is φ = 17035392.

The previous prime is 18493883. The next prime is 18493903. The reversal of 18493891 is 19839481.

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 18493891 - 2³ = 18493883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18493291) 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 7 ways as a sum of consecutive naturals, for example, 6510 + ... + 8908.

It is an arithmetic number, because the mean of its divisors is an integer number (2494800).

Almost surely, 2^18493891 is an apocalyptic number.

18493891 is a deficient number, since it is larger than the sum of its proper divisors (1464509).

18493891 is a wasteful number, since it uses less digits than its factorization.

18493891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3005.

The product of its digits is 62208, while the sum is 43.

The square root of 18493891 is about 4300.4524180602. The cubic root of 18493891 is about 264.4495087196.

The spelling of 18493891 in words is "eighteen million, four hundred ninety-three thousand, eight hundred ninety-one".