18391057 has 8 divisors (see below), whose sum is σ = 19049184. Its totient is φ = 17743488.

The previous prime is 18391019. The next prime is 18391123. The reversal of 18391057 is 75019381.

It is a happy number.

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 18391057 - 2⁷ = 18390929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18391157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 993 + ... + 6145.

It is an arithmetic number, because the mean of its divisors is an integer number (2381148).

Almost surely, 2^18391057 is an apocalyptic number.

It is an amenable number.

18391057 is a deficient number, since it is larger than the sum of its proper divisors (658127).

18391057 is an equidigital number, since it uses as much as digits as its factorization.

18391057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5279.

The product of its (nonzero) digits is 7560, while the sum is 34.

The square root of 18391057 is about 4288.4795673991. The cubic root of 18391057 is about 263.9584463600.

The spelling of 18391057 in words is "eighteen million, three hundred ninety-one thousand, fifty-seven".