138784538 has 4 divisors (see below), whose sum is σ = 208176810. Its totient is φ = 69392268.

The previous prime is 138784519. The next prime is 138784559. The reversal of 138784538 is 835487831.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 835487831 = 17 ⋅49146343.

It can be written as a sum of positive squares in only one way, i.e., 134954689 + 3829849 = 11617^2 + 1957^2 .

It is a super-2 number, since 2×138784538² = 38522295975746888, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 138784492 and 138784501.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34696133 + ... + 34696136.

Almost surely, 2^138784538 is an apocalyptic number.

138784538 is a deficient number, since it is larger than the sum of its proper divisors (69392272).

138784538 is an equidigital number, since it uses as much as digits as its factorization.

138784538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69392271.

The product of its digits is 645120, while the sum is 47.

The square root of 138784538 is about 11780.6849546196. The cubic root of 138784538 is about 517.7423548409.

The spelling of 138784538 in words is "one hundred thirty-eight million, seven hundred eighty-four thousand, five hundred thirty-eight".