138647808 has 144 divisors (see below), whose sum is σ = 441831040. Its totient is φ = 42633216.

The previous prime is 138647783. The next prime is 138647809. The reversal of 138647808 is 808746831.

It is a tau number, because it is divible by the number of its divisors (144).

It is a taxicab number since it can be written as a sum of two cubes in more than one way. Here 138647808 = 108³ + 516³ = 279³ + 489³.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138647809) 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, 89085 + ... + 90627.

Almost surely, 2^138647808 is an apocalyptic number.

138647808 is a gapful number since it is divisible by the number (18) 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 138647808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (220915520).

138647808 is an abundant number, since it is smaller than the sum of its proper divisors (303183232).

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

138647808 is a wasteful number, since it uses less digits than its factorization.

138647808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1581 (or 1561 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The square root of 138647808 is about 11774.8803815580. The cubic root of 138647808 is about 517.5722730398.

It can be divided in two parts, 1386 and 47808, that added together give a palindrome (49194).

The spelling of 138647808 in words is "one hundred thirty-eight million, six hundred forty-seven thousand, eight hundred eight".