138609538 has 12 divisors (see below), whose sum is σ = 208878210. Its totient is φ = 68984736.

The previous prime is 138609481. The next prime is 138609547. The reversal of 138609538 is 835906831.

It can be written as a sum of positive squares in 3 ways, for example, as 123810129 + 14799409 = 11127^2 + 3847^2 .

It is a junction number, because it is equal to n+sod(n) for n = 138609494 and 138609503.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 243318 + ... + 243886.

Almost surely, 2^138609538 is an apocalyptic number.

138609538 is a deficient number, since it is larger than the sum of its proper divisors (70268672).

138609538 is an frugal number, since it uses more digits than its factorization.

138609538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1269 (or 920 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 43.

The square root of 138609538 is about 11773.2551998162. The cubic root of 138609538 is about 517.5246480205.

The spelling of 138609538 in words is "one hundred thirty-eight million, six hundred nine thousand, five hundred thirty-eight".