138805506 has 96 divisors (see below), whose sum is σ = 361939968. Its totient is φ = 37588320.

The previous prime is 138805501. The next prime is 138805519. The reversal of 138805506 is 605508831.

It is not an unprimeable number, because it can be changed into a prime (138805501) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 611365 + ... + 611591.

It is an arithmetic number, because the mean of its divisors is an integer number (3770208).

Almost surely, 2^138805506 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138805506, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (180969984).

138805506 is an abundant number, since it is smaller than the sum of its proper divisors (223134462).

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

138805506 is a wasteful number, since it uses less digits than its factorization.

138805506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476 (or 473 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 138805506 is about 11781.5748522852. The cubic root of 138805506 is about 517.7684275701.

The spelling of 138805506 in words is "one hundred thirty-eight million, eight hundred five thousand, five hundred six".