129097440 has 144 divisors (see below), whose sum is σ = 452638368. Its totient is φ = 33481728.

The previous prime is 129097433. The next prime is 129097471. The reversal of 129097440 is 44790921.

129097440 is a `hidden beast` number, since 129 + 0 + 97 + 440 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×129097440² = 33332298029107200, 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 = 129097395 and 129097404.

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, 52069 + ... + 54491.

It is an arithmetic number, because the mean of its divisors is an integer number (3143322).

Almost surely, 2^129097440 is an apocalyptic number.

129097440 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 129097440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (226319184).

129097440 is an abundant number, since it is smaller than the sum of its proper divisors (323540928).

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

129097440 is a wasteful number, since it uses less digits than its factorization.

129097440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2481 (or 2470 counting only the distinct ones).

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

The square root of 129097440 is about 11362.1054386940. The cubic root of 129097440 is about 505.4046229433.

The spelling of 129097440 in words is "one hundred twenty-nine million, ninety-seven thousand, four hundred forty".