138581280 has 360 divisors, whose sum is σ = 533579508. Its totient is φ = 33841152.

The previous prime is 138581251. The next prime is 138581291. The reversal of 138581280 is 82185831.

It can be written as a sum of positive squares in 6 ways, for example, as 123743376 + 14837904 = 11124^2 + 3852^2 .

It is a tau number, because it is divible by the number of its divisors (360).

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

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 3745422 + ... + 3745458.

Almost surely, 2^138581280 is an apocalyptic number.

138581280 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 138581280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (266789754).

138581280 is an abundant number, since it is smaller than the sum of its proper divisors (394998228).

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

138581280 is a wasteful number, since it uses less digits than its factorization.

138581280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 36.

The square root of 138581280 is about 11772.0550457429. The cubic root of 138581280 is about 517.4894767866.

The spelling of 138581280 in words is "one hundred thirty-eight million, five hundred eighty-one thousand, two hundred eighty".