138250728 has 144 divisors (see below), whose sum is σ = 470564640. Its totient is φ = 35893440.

The previous prime is 138250691. The next prime is 138250733. The reversal of 138250728 is 827052831.

It is a super-2 number, since 2×138250728² = 38226527585059968, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 138250692 and 138250701.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 59851 + ... + 62117.

It is an arithmetic number, because the mean of its divisors is an integer number (3267810).

Almost surely, 2^138250728 is an apocalyptic number.

138250728 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 138250728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (235282320).

138250728 is an abundant number, since it is smaller than the sum of its proper divisors (332313912).

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

138250728 is a wasteful number, since it uses less digits than its factorization.

138250728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2308 (or 2290 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 138250728 is about 11758.0069739731. The cubic root of 138250728 is about 517.0777007104.

The spelling of 138250728 in words is "one hundred thirty-eight million, two hundred fifty thousand, seven hundred twenty-eight".