129321440 has 96 divisors (see below), whose sum is σ = 323326080. Its totient is φ = 48799744.

The previous prime is 129321427. The next prime is 129321461. The reversal of 129321440 is 44123921.

It is a congruent number.

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, 217784 + ... + 218376.

It is an arithmetic number, because the mean of its divisors is an integer number (3367980).

Almost surely, 2^129321440 is an apocalyptic number.

129321440 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 129321440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (161663040).

129321440 is an abundant number, since it is smaller than the sum of its proper divisors (194004640).

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

129321440 is a wasteful number, since it uses less digits than its factorization.

129321440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 684 (or 676 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 129321440 is about 11371.9584944723. The cubic root of 129321440 is about 505.6967671832.

The spelling of 129321440 in words is "one hundred twenty-nine million, three hundred twenty-one thousand, four hundred forty".