18129 has 4 divisors (see below), whose sum is σ = 24176. Its totient is φ = 12084.

The previous prime is 18127. The next prime is 18131. The reversal of 18129 is 92181.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 92181 = 3 ⋅30727.

It is an interprime number because it is at equal distance from previous prime (18127) and next prime (18131).

It is not a de Polignac number, because 18129 - 2¹ = 18127 is a prime.

It is a D-number.

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

It is a Duffinian number.

It is a plaindrome in base 15.

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (18121) 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, 3019 + ... + 3024.

It is an arithmetic number, because the mean of its divisors is an integer number (6044).

2¹⁸¹²⁹ is an apocalyptic number.

It is an amenable number.

18129 is a deficient number, since it is larger than the sum of its proper divisors (6047).

18129 is an equidigital number, since it uses as much as digits as its factorization.

18129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6046.

The product of its digits is 144, while the sum is 21.

The square root of 18129 is about 134.6439749859. The cubic root of 18129 is about 26.2698715745.

It can be divided in two parts, 181 and 29, that added together give a triangular number (210 = T₂₀).

The spelling of 18129 in words is "eighteen thousand, one hundred twenty-nine".