138209040 has 120 divisors (see below), whose sum is σ = 488629440. Its totient is φ = 34912512.

The previous prime is 138209039. The next prime is 138209063. The reversal of 138209040 is 40902831.

It is a tau number, because it is divible by the number of its divisors (120).

It is a junction number, because it is equal to n+sod(n) for n = 138208995 and 138209013.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8629 + ... + 18731.

It is an arithmetic number, because the mean of its divisors is an integer number (4071912).

Almost surely, 2^138209040 is an apocalyptic number.

138209040 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 138209040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (244314720).

138209040 is an abundant number, since it is smaller than the sum of its proper divisors (350420400).

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

138209040 is a wasteful number, since it uses less digits than its factorization.

138209040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10141 (or 10132 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 138209040 is about 11756.2340908983. The cubic root of 138209040 is about 517.0257224375.

The spelling of 138209040 in words is "one hundred thirty-eight million, two hundred nine thousand, forty".