18138 has 8 divisors (see below), whose sum is σ = 36288. Its totient is φ = 6044.

The previous prime is 18133. The next prime is 18143. The reversal of 18138 is 83181.

18138 = T₁₂ + T₁₃ + ... + T₄₇.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (18133) and next prime (18143).

It is a sphenic number, since it is the product of 3 distinct primes.

18138 is an admirable number.

It is a Curzon number.

It is a plaindrome in base 11.

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (18131) by changing a digit.

18138 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1506 + ... + 1517.

It is an arithmetic number, because the mean of its divisors is an integer number (4536).

2¹⁸¹³⁸ is an apocalyptic number.

18138 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18144).

18138 is a wasteful number, since it uses less digits than its factorization.

18138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3028.

The product of its digits is 192, while the sum is 21.

The square root of 18138 is about 134.6773923121. The cubic root of 18138 is about 26.2742180126.

The spelling of 18138 in words is "eighteen thousand, one hundred thirty-eight".