138691008 has 112 divisors (see below), whose sum is σ = 413064960. Its totient is φ = 45626112.

The previous prime is 138691001. The next prime is 138691009. The reversal of 138691008 is 800196831.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138691001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 142941 + ... + 143907.

It is an arithmetic number, because the mean of its divisors is an integer number (3688080).

Almost surely, 2^138691008 is an apocalyptic number.

138691008 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 138691008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (206532480).

138691008 is an abundant number, since it is smaller than the sum of its proper divisors (274373952).

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

138691008 is an equidigital number, since it uses as much as digits as its factorization.

138691008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1071 (or 1055 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 138691008 is about 11776.7146522279. The cubic root of 138691008 is about 517.6260226583.

The spelling of 138691008 in words is "one hundred thirty-eight million, six hundred ninety-one thousand, eight".