138221736 has 64 divisors (see below), whose sum is σ = 355380480. Its totient is φ = 44778240.

The previous prime is 138221731. The next prime is 138221753. The reversal of 138221736 is 637122831.

It is a junction number, because it is equal to n+sod(n) for n = 138221697 and 138221706.

It is not an unprimeable number, because it can be changed into a prime (138221731) 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, 203830 + ... + 204506.

It is an arithmetic number, because the mean of its divisors is an integer number (5552820).

Almost surely, 2^138221736 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138221736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (177690240).

138221736 is an abundant number, since it is smaller than the sum of its proper divisors (217158744).

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

138221736 is a wasteful number, since it uses less digits than its factorization.

138221736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 914 (or 910 counting only the distinct ones).

The product of its digits is 12096, while the sum is 33.

The square root of 138221736 is about 11756.7740473312. The cubic root of 138221736 is about 517.0415534270.

The spelling of 138221736 in words is "one hundred thirty-eight million, two hundred twenty-one thousand, seven hundred thirty-six".