138618 has 32 divisors (see below), whose sum is σ = 328320. Its totient is φ = 43200.

The previous prime is 138617. The next prime is 138629. The reversal of 138618 is 816831.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 138591 and 138600.

It is not an unprimeable number, because it can be changed into a prime (138617) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 843 + ... + 993.

It is an arithmetic number, because the mean of its divisors is an integer number (10260).

2¹³⁸⁶¹⁸ is an apocalyptic number.

138618 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 138618, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (164160).

138618 is an abundant number, since it is smaller than the sum of its proper divisors (189702).

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

138618 is a wasteful number, since it uses less digits than its factorization.

138618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 179 (or 173 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 138618 is about 372.3143832838. The cubic root of 138618 is about 51.7535179293.

The spelling of 138618 in words is "one hundred thirty-eight thousand, six hundred eighteen".