18391457 has 8 divisors (see below), whose sum is σ = 21141696. Its totient is φ = 15671952.

The previous prime is 18391447. The next prime is 18391459. The reversal of 18391457 is 75419381.

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 18391457 - 2⁴ = 18391441 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 18391457.

It is not an unprimeable number, because it can be changed into a prime (18391459) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6383 + ... + 8804.

It is an arithmetic number, because the mean of its divisors is an integer number (2642712).

Almost surely, 2^18391457 is an apocalyptic number.

It is an amenable number.

18391457 is a deficient number, since it is larger than the sum of its proper divisors (2750239).

18391457 is a wasteful number, since it uses less digits than its factorization.

18391457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15367.

The product of its digits is 30240, while the sum is 38.

The square root of 18391457 is about 4288.5262037208. The cubic root of 18391457 is about 263.9603600186.

The spelling of 18391457 in words is "eighteen million, three hundred ninety-one thousand, four hundred fifty-seven".