138634259 has 4 divisors (see below), whose sum is σ = 138657816. Its totient is φ = 138610704.

The previous prime is 138634217. The next prime is 138634267. The reversal of 138634259 is 952436831.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 952436831 = 23 ⋅41410297.

It is a cyclic number.

It is not a de Polignac number, because 138634259 - 2¹⁶ = 138568723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138637259) 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, 5447 + ... + 17519.

It is an arithmetic number, because the mean of its divisors is an integer number (34664454).

Almost surely, 2^138634259 is an apocalyptic number.

138634259 is a deficient number, since it is larger than the sum of its proper divisors (23557).

138634259 is a wasteful number, since it uses less digits than its factorization.

138634259 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23556.

The product of its digits is 155520, while the sum is 41.

The square root of 138634259 is about 11774.3050325699. The cubic root of 138634259 is about 517.5554130181. Note that the first 3 decimals are identical.

The spelling of 138634259 in words is "one hundred thirty-eight million, six hundred thirty-four thousand, two hundred fifty-nine".