138640672 has 12 divisors (see below), whose sum is σ = 272948886. Its totient is φ = 69320320.

The previous prime is 138640669. The next prime is 138640681. The reversal of 138640672 is 276046831.

It can be written as a sum of positive squares in only one way, i.e., 80209936 + 58430736 = 8956^2 + 7644^2 .

It is a super-3 number, since 3×138640672³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2166229 + ... + 2166292.

Almost surely, 2^138640672 is an apocalyptic number.

It is an amenable number.

138640672 is a deficient number, since it is larger than the sum of its proper divisors (134308214).

138640672 is an equidigital number, since it uses as much as digits as its factorization.

138640672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4332531 (or 4332523 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 37.

The square root of 138640672 is about 11774.5773597187. The cubic root of 138640672 is about 517.5633933247.

The spelling of 138640672 in words is "one hundred thirty-eight million, six hundred forty thousand, six hundred seventy-two".