129645440 has 64 divisors (see below), whose sum is σ = 312046560. Its totient is φ = 51505152.

The previous prime is 129645437. The next prime is 129645443. The reversal of 129645440 is 44546921.

It is an interprime number because it is at equal distance from previous prime (129645437) and next prime (129645443).

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×129645440² = 33615880225587200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 129645440.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129645443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 106274 + ... + 107486.

Almost surely, 2^129645440 is an apocalyptic number.

129645440 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 129645440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (156023280).

129645440 is an abundant number, since it is smaller than the sum of its proper divisors (182401120).

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

129645440 is a wasteful number, since it uses less digits than its factorization.

129645440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1399 (or 1387 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 35.

The square root of 129645440 is about 11386.1951502686. The cubic root of 129645440 is about 506.1187366841.

The spelling of 129645440 in words is "one hundred twenty-nine million, six hundred forty-five thousand, four hundred forty".