18857 has 4 divisors (see below), whose sum is σ = 19140. Its totient is φ = 18576.

The previous prime is 18839. The next prime is 18859. The reversal of 18857 is 75881.

It is a happy number.

18857 is nontrivially palindromic in base 9.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 15376 + 3481 = 124^2 + 59^2 .

It is a cyclic number.

It is not a de Polignac number, because 18857 - 2⁶ = 18793 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (18859) 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 3 ways as a sum of consecutive naturals, for example, 23 + ... + 195.

It is an arithmetic number, because the mean of its divisors is an integer number (4785).

2¹⁸⁸⁵⁷ is an apocalyptic number.

It is an amenable number.

18857 is a deficient number, since it is larger than the sum of its proper divisors (283).

18857 is a wasteful number, since it uses less digits than its factorization.

18857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 282.

The product of its digits is 2240, while the sum is 29.

The square root of 18857 is about 137.3207923076. The cubic root of 18857 is about 26.6169037224.

The spelling of 18857 in words is "eighteen thousand, eight hundred fifty-seven".