138421440 has 224 divisors, whose sum is σ = 502676160. Its totient is φ = 35831808.

The previous prime is 138421411. The next prime is 138421487. The reversal of 138421440 is 44124831.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 319464 + ... + 319896.

It is an arithmetic number, because the mean of its divisors is an integer number (2244090).

Almost surely, 2^138421440 is an apocalyptic number.

138421440 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 138421440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (251338080).

138421440 is an abundant number, since it is smaller than the sum of its proper divisors (364254720).

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

138421440 is a wasteful number, since it uses less digits than its factorization.

138421440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 496 (or 480 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 138421440 is about 11765.2641279319. The cubic root of 138421440 is about 517.2904423529.

The spelling of 138421440 in words is "one hundred thirty-eight million, four hundred twenty-one thousand, four hundred forty".