138644872 has 8 divisors (see below), whose sum is σ = 259959150. Its totient is φ = 69322432.

The previous prime is 138644837. The next prime is 138644923. The reversal of 138644872 is 278446831.

It can be written as a sum of positive squares in only one way, i.e., 138438756 + 206116 = 11766^2 + 454^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8665297 + ... + 8665312.

Almost surely, 2^138644872 is an apocalyptic number.

It is an amenable number.

138644872 is a deficient number, since it is larger than the sum of its proper divisors (121314278).

138644872 is a wasteful number, since it uses less digits than its factorization.

138644872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17330615 (or 17330611 counting only the distinct ones).

The product of its digits is 258048, while the sum is 43.

The square root of 138644872 is about 11774.7557087185. The cubic root of 138644872 is about 517.5686196513.

The spelling of 138644872 in words is "one hundred thirty-eight million, six hundred forty-four thousand, eight hundred seventy-two".