18729 has 6 divisors (see below), whose sum is σ = 27066. Its totient is φ = 12480.

The previous prime is 18719. The next prime is 18731. The reversal of 18729 is 92781.

It can be written as a sum of positive squares in only one way, i.e., 15129 + 3600 = 123^2 + 60^2 .

It is not a de Polignac number, because 18729 - 2⁴ = 18713 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (18719) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1032 + ... + 1049.

It is an arithmetic number, because the mean of its divisors is an integer number (4511).

2¹⁸⁷²⁹ is an apocalyptic number.

It is an amenable number.

18729 is a deficient number, since it is larger than the sum of its proper divisors (8337).

18729 is a wasteful number, since it uses less digits than its factorization.

18729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2087 (or 2084 counting only the distinct ones).

The product of its digits is 1008, while the sum is 27.

The square root of 18729 is about 136.8539367355. The cubic root of 18729 is about 26.5565423778.

It can be divided in two parts, 1872 and 9, that added together give a palindrome (1881).

The spelling of 18729 in words is "eighteen thousand, seven hundred twenty-nine".