138791808 has 192 divisors, whose sum is σ = 446331600. Its totient is φ = 41140224.

The previous prime is 138791803. The next prime is 138791813. The reversal of 138791808 is 808197831.

It is an interprime number because it is at equal distance from previous prime (138791803) and next prime (138791813).

It is a tau number, because it is divible by the number of its divisors (192).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138791803) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 371910 + ... + 372282.

Almost surely, 2^138791808 is an apocalyptic number.

138791808 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 138791808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (223165800).

138791808 is an abundant number, since it is smaller than the sum of its proper divisors (307539792).

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

138791808 is a wasteful number, since it uses less digits than its factorization.

138791808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 429 (or 414 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 45.

The square root of 138791808 is about 11780.9935064917. The cubic root of 138791808 is about 517.7513950439.

The spelling of 138791808 in words is "one hundred thirty-eight million, seven hundred ninety-one thousand, eight hundred eight".