138509910 has 288 divisors, whose sum is σ = 478033920. Its totient is φ = 27181440.

The previous prime is 138509909. The next prime is 138509911. The reversal of 138509910 is 19905831.

It is a happy number.

138509910 is a `hidden beast` number, since 138 + 509 + 9 + 10 = 666.

It is an interprime number because it is at equal distance from previous prime (138509909) and next prime (138509911).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138509911) by changing a digit.

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 143 ways as a sum of consecutive naturals, for example, 1753251 + ... + 1753329.

It is an arithmetic number, because the mean of its divisors is an integer number (1659840).

Almost surely, 2^138509910 is an apocalyptic number.

138509910 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 138509910, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (239016960).

138509910 is an abundant number, since it is smaller than the sum of its proper divisors (339524010).

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

138509910 is a wasteful number, since it uses less digits than its factorization.

138509910 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 36.

The square root of 138509910 is about 11769.0233239636. The cubic root of 138509910 is about 517.4006250407.

The spelling of 138509910 in words is "one hundred thirty-eight million, five hundred nine thousand, nine hundred ten".