129840440 has 48 divisors (see below), whose sum is σ = 299595240. Its totient is φ = 50643200.

The previous prime is 129840419. The next prime is 129840443. The reversal of 129840440 is 44048921.

It is a junction number, because it is equal to n+sod(n) for n = 129840397 and 129840406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129840443) 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, 66275 + ... + 68205.

Almost surely, 2^129840440 is an apocalyptic number.

129840440 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 129840440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (149797620).

129840440 is an abundant number, since it is smaller than the sum of its proper divisors (169754800).

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

129840440 is a wasteful number, since it uses less digits than its factorization.

129840440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2024 (or 1979 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 129840440 is about 11394.7549337403. The cubic root of 129840440 is about 506.3723610137.

The spelling of 129840440 in words is "one hundred twenty-nine million, eight hundred forty thousand, four hundred forty".