138635720 has 64 divisors (see below), whose sum is σ = 336061440. Its totient is φ = 51321600.

The previous prime is 138635677. The next prime is 138635729. The reversal of 138635720 is 27536831.

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (138635729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26090 + ... + 30950.

It is an arithmetic number, because the mean of its divisors is an integer number (5250960).

Almost surely, 2^138635720 is an apocalyptic number.

138635720 is a gapful number since it is divisible by the number (10) 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 138635720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (168030720).

138635720 is an abundant number, since it is smaller than the sum of its proper divisors (197425720).

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

138635720 is a wasteful number, since it uses less digits than its factorization.

138635720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4926 (or 4922 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 35.

The square root of 138635720 is about 11774.3670742847. The cubic root of 138635720 is about 517.5572311012.

The spelling of 138635720 in words is "one hundred thirty-eight million, six hundred thirty-five thousand, seven hundred twenty".