138690 has 48 divisors (see below), whose sum is σ = 381888. Its totient is φ = 34848.

The previous prime is 138683. The next prime is 138727. The reversal of 138690 is 96831.

It is a super-2 number, since 2×138690² = 38469832200, which contains 22 as substring.

It is a nialpdrome in base 11.

It is an unprimeable number.

138690 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 23 ways as a sum of consecutive naturals, for example, 2037 + ... + 2103.

It is an arithmetic number, because the mean of its divisors is an integer number (7956).

2¹³⁸⁶⁹⁰ is an apocalyptic number.

138690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 138690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (190944).

138690 is an abundant number, since it is smaller than the sum of its proper divisors (243198).

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

138690 is a wasteful number, since it uses less digits than its factorization.

138690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 138690 is about 372.4110632084. The cubic root of 138690 is about 51.7624768628.

It can be divided in two parts, 138 and 690, that added together give a palindrome (828).

The spelling of 138690 in words is "one hundred thirty-eight thousand, six hundred ninety".