138640432 has 80 divisors (see below), whose sum is σ = 321820672. Its totient is φ = 56609280.

The previous prime is 138640429. The next prime is 138640507. The reversal of 138640432 is 234046831.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a junction number, because it is equal to n+sod(n) for n = 138640394 and 138640403.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 253183 + ... + 253729.

Almost surely, 2^138640432 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138640432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160910336).

138640432 is an abundant number, since it is smaller than the sum of its proper divisors (183180240).

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

138640432 is a wasteful number, since it uses less digits than its factorization.

138640432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 666 (or 660 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 31.

The square root of 138640432 is about 11774.5671682657. The cubic root of 138640432 is about 517.5630946743.

The spelling of 138640432 in words is "one hundred thirty-eight million, six hundred forty thousand, four hundred thirty-two".