138438664 has 64 divisors (see below), whose sum is σ = 320947200. Its totient is φ = 54514944.

The previous prime is 138438661. The next prime is 138438689. The reversal of 138438664 is 466834831.

It is a self number, because there is not a number n which added to its sum of digits gives 138438664.

It is not an unprimeable number, because it can be changed into a prime (138438661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 288777 + ... + 289255.

It is an arithmetic number, because the mean of its divisors is an integer number (5014800).

Almost surely, 2^138438664 is an apocalyptic number.

138438664 is a gapful number since it is divisible by the number (14) 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 138438664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160473600).

138438664 is an abundant number, since it is smaller than the sum of its proper divisors (182508536).

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

138438664 is a wasteful number, since it uses less digits than its factorization.

138438664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 902 (or 898 counting only the distinct ones).

The product of its digits is 331776, while the sum is 43.

The square root of 138438664 is about 11765.9960904294. The cubic root of 138438664 is about 517.3118972206.

The spelling of 138438664 in words is "one hundred thirty-eight million, four hundred thirty-eight thousand, six hundred sixty-four".