138613 has 4 divisors (see below), whose sum is σ = 140140. Its totient is φ = 137088.

The previous prime is 138599. The next prime is 138617. The reversal of 138613 is 316831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 316831 = 37 ⋅8563.

It can be written as a sum of positive squares in 2 ways, for example, as 31684 + 106929 = 178^2 + 327^2 .

It is a cyclic number.

It is not a de Polignac number, because 138613 - 2⁵ = 138581 is a prime.

It is a Duffinian number.

138613 is a lucky number.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 618 + ... + 811.

It is an arithmetic number, because the mean of its divisors is an integer number (35035).

2¹³⁸⁶¹³ is an apocalyptic number.

It is an amenable number.

138613 is a deficient number, since it is larger than the sum of its proper divisors (1527).

138613 is an equidigital number, since it uses as much as digits as its factorization.

138613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1526.

The product of its digits is 432, while the sum is 22.

The square root of 138613 is about 372.3076684679. The cubic root of 138613 is about 51.7528956660.

The spelling of 138613 in words is "one hundred thirty-eight thousand, six hundred thirteen".