138693928 has 16 divisors (see below), whose sum is σ = 260182260. Its totient is φ = 69312000.

The previous prime is 138693923. The next prime is 138693937. The reversal of 138693928 is 829396831.

It can be written as a sum of positive squares in 2 ways, for example, as 105308644 + 33385284 = 10262^2 + 5778^2 .

Its product of digits (559872) is a multiple of the sum of its prime factors (8748).

It is not an unprimeable number, because it can be changed into a prime (138693923) 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, 21478 + ... + 27178.

Almost surely, 2^138693928 is an apocalyptic number.

It is an amenable number.

138693928 is a deficient number, since it is larger than the sum of its proper divisors (121488332).

138693928 is a wasteful number, since it uses less digits than its factorization.

138693928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8748 (or 8744 counting only the distinct ones).

The product of its digits is 559872, while the sum is 49.

The square root of 138693928 is about 11776.8386250301. The cubic root of 138693928 is about 517.6296553317.

The spelling of 138693928 in words is "one hundred thirty-eight million, six hundred ninety-three thousand, nine hundred twenty-eight".