129709440 has 192 divisors, whose sum is σ = 512048160. Its totient is φ = 29638656.

The previous prime is 129709429. The next prime is 129709441. The reversal of 129709440 is 44907921.

It is a tau number, because it is divible by the number of its divisors (192).

It is a super-2 number, since 2×129709440² = 33649077650227200, which contains 22 as substring.

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 = 129709395 and 129709404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129709441) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 38712 + ... + 41928.

Almost surely, 2^129709440 is an apocalyptic number.

129709440 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 129709440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (256024080).

129709440 is an abundant number, since it is smaller than the sum of its proper divisors (382338720).

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

129709440 is a wasteful number, since it uses less digits than its factorization.

129709440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3249 (or 3234 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 129709440 is about 11389.0052243381. The cubic root of 129709440 is about 506.2020055095.

The spelling of 129709440 in words is "one hundred twenty-nine million, seven hundred nine thousand, four hundred forty".