138805728 has 48 divisors (see below), whose sum is σ = 371253456. Its totient is φ = 45393920.

The previous prime is 138805721. The next prime is 138805757. The reversal of 138805728 is 827508831.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (48).

It is a self number, because there is not a number n which added to its sum of digits gives 138805728.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138805721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8553 + ... + 18728.

It is an arithmetic number, because the mean of its divisors is an integer number (7734447).

Almost surely, 2^138805728 is an apocalyptic number.

It is an amenable number.

138805728 is an abundant number, since it is smaller than the sum of its proper divisors (232447728).

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

138805728 is a wasteful number, since it uses less digits than its factorization.

138805728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27347 (or 27339 counting only the distinct ones).

The product of its (nonzero) digits is 107520, while the sum is 42.

The square root of 138805728 is about 11781.5842737724. The cubic root of 138805728 is about 517.7687036027.

The spelling of 138805728 in words is "one hundred thirty-eight million, eight hundred five thousand, seven hundred twenty-eight".