129129840 has 120 divisors (see below), whose sum is σ = 495631968. Its totient is φ = 29514240.

The previous prime is 129129839. The next prime is 129129851. The reversal of 129129840 is 48921921.

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 = 129129795 and 129129804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7771 + ... + 17850.

Almost surely, 2^129129840 is an apocalyptic number.

129129840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

129129840 is an abundant number, since it is smaller than the sum of its proper divisors (366502128).

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

129129840 is a wasteful number, since it uses less digits than its factorization.

129129840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25647 (or 25638 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 129129840 is about 11363.5311413310. The cubic root of 129129840 is about 505.4469004150.

The spelling of 129129840 in words is "one hundred twenty-nine million, one hundred twenty-nine thousand, eight hundred forty".