138826728 has 96 divisors (see below), whose sum is σ = 388282440. Its totient is φ = 44789760.

The previous prime is 138826703. The next prime is 138826729. The reversal of 138826728 is 827628831.

138826728 is a `hidden beast` number, since 1 + 388 + 267 + 2 + 8 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 55980324 + 82846404 = 7482^2 + 9102^2 .

It is not an unprimeable number, because it can be changed into a prime (138826729) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 320400 + ... + 320832.

Almost surely, 2^138826728 is an apocalyptic number.

138826728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138826728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (194141220).

138826728 is an abundant number, since it is smaller than the sum of its proper divisors (249455712).

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

138826728 is a wasteful number, since it uses less digits than its factorization.

138826728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 579 (or 572 counting only the distinct ones).

The product of its digits is 258048, while the sum is 45.

The square root of 138826728 is about 11782.4754614639. The cubic root of 138826728 is about 517.7948134629.

The spelling of 138826728 in words is "one hundred thirty-eight million, eight hundred twenty-six thousand, seven hundred twenty-eight".