138209280 has 192 divisors, whose sum is σ = 483537600. Its totient is φ = 33423360.

The previous prime is 138209261. The next prime is 138209293. The reversal of 138209280 is 82902831.

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

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 337716 + ... + 338124.

It is an arithmetic number, because the mean of its divisors is an integer number (2518425).

Almost surely, 2^138209280 is an apocalyptic number.

138209280 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 138209280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (241768800).

138209280 is an abundant number, since it is smaller than the sum of its proper divisors (345328320).

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

138209280 is a wasteful number, since it uses less digits than its factorization.

138209280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 450 (or 430 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 138209280 is about 11756.2442982442. The cubic root of 138209280 is about 517.0260217090.

The spelling of 138209280 in words is "one hundred thirty-eight million, two hundred nine thousand, two hundred eighty".