138538 has 8 divisors (see below), whose sum is σ = 209988. Its totient is φ = 68544.

The previous prime is 138517. The next prime is 138547. The reversal of 138538 is 835831.

It can be written as a sum of positive squares in 2 ways, for example, as 82369 + 56169 = 287^2 + 237^2 .

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

It is an unprimeable number.

138538 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, 81 + ... + 532.

2¹³⁸⁵³⁸ is an apocalyptic number.

138538 is a deficient number, since it is larger than the sum of its proper divisors (71450).

138538 is a wasteful number, since it uses less digits than its factorization.

138538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 728.

The product of its digits is 2880, while the sum is 28.

The square root of 138538 is about 372.2069316926. The cubic root of 138538 is about 51.7435599196.

It can be divided in two parts, 13853 and 8, that added together give a triangular number (13861 = T₁₆₆).

The spelling of 138538 in words is "one hundred thirty-eight thousand, five hundred thirty-eight".