138228090 has 128 divisors (see below), whose sum is σ = 445519872. Its totient is φ = 26507520.

The previous prime is 138228089. The next prime is 138228107. The reversal of 138228090 is 90822831.

138228090 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 27729 + ... + 32331.

It is an arithmetic number, because the mean of its divisors is an integer number (3480624).

Almost surely, 2^138228090 is an apocalyptic number.

138228090 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 138228090, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (222759936).

138228090 is an abundant number, since it is smaller than the sum of its proper divisors (307291782).

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

138228090 is a wasteful number, since it uses less digits than its factorization.

138228090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4644.

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 138228090 is about 11757.0442714145. The cubic root of 138228090 is about 517.0494760393.

It can be divided in two parts, 13822 and 8090, that added together give a palindrome (21912).

The spelling of 138228090 in words is "one hundred thirty-eight million, two hundred twenty-eight thousand, ninety".