138402440 has 64 divisors (see below), whose sum is σ = 359717760. Its totient is φ = 47365120.

The previous prime is 138402427. The next prime is 138402461. The reversal of 138402440 is 44204831.

138402440 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

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, 1772 + ... + 16731.

It is an arithmetic number, because the mean of its divisors is an integer number (5620590).

Almost surely, 2^138402440 is an apocalyptic number.

138402440 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 138402440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (179858880).

138402440 is an abundant number, since it is smaller than the sum of its proper divisors (221315320).

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

138402440 is a wasteful number, since it uses less digits than its factorization.

138402440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18542 (or 18538 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 26.

The square root of 138402440 is about 11764.4566385363. The cubic root of 138402440 is about 517.2667731676.

The spelling of 138402440 in words is "one hundred thirty-eight million, four hundred two thousand, four hundred forty".