138473840 has 80 divisors (see below), whose sum is σ = 352745280. Its totient is φ = 50319360.

The previous prime is 138473837. The next prime is 138473849. The reversal of 138473840 is 48374831.

138473840 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 138473794 and 138473803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138473849) 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, 37685 + ... + 41195.

It is an arithmetic number, because the mean of its divisors is an integer number (4409316).

Almost surely, 2^138473840 is an apocalyptic number.

138473840 is a gapful number since it is divisible by the number (10) 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 138473840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (176372640).

138473840 is an abundant number, since it is smaller than the sum of its proper divisors (214271440).

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

138473840 is a wasteful number, since it uses less digits than its factorization.

138473840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3570 (or 3564 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 38.

The square root of 138473840 is about 11767.4908115537. The cubic root of 138473840 is about 517.3557082527.

Subtracting from 138473840 its reverse (48374831), we obtain a palindrome (90099009).

The spelling of 138473840 in words is "one hundred thirty-eight million, four hundred seventy-three thousand, eight hundred forty".