138940928 has 40 divisors (see below), whose sum is σ = 317277312. Its totient is φ = 59544576.

The previous prime is 138940927. The next prime is 138940937. The reversal of 138940928 is 829049831.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (138940927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15800 + ... + 22967.

Almost surely, 2^138940928 is an apocalyptic number.

It is an amenable number.

138940928 is an abundant number, since it is smaller than the sum of its proper divisors (178336384).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138940928 is an frugal number, since it uses more digits than its factorization.

138940928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38792 (or 38776 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 44.

The square root of 138940928 is about 11787.3206455072. The cubic root of 138940928 is about 517.9367552964.

The spelling of 138940928 in words is "one hundred thirty-eight million, nine hundred forty thousand, nine hundred twenty-eight".