138493440 has 120 divisors (see below), whose sum is σ = 479721528. Its totient is φ = 36925440.

The previous prime is 138493409. The next prime is 138493447. The reversal of 138493440 is 44394831.

138493440 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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

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

It is a junction number, because it is equal to n+sod(n) for n = 138493395 and 138493404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138493447) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20035 + ... + 26045.

Almost surely, 2^138493440 is an apocalyptic number.

138493440 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 138493440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (239860764).

138493440 is an abundant number, since it is smaller than the sum of its proper divisors (341228088).

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

138493440 is an equidigital number, since it uses as much as digits as its factorization.

138493440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6040 (or 6021 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 138493440 is about 11768.3235849462. The cubic root of 138493440 is about 517.3801164574.

The spelling of 138493440 in words is "one hundred thirty-eight million, four hundred ninety-three thousand, four hundred forty".