129297640 has 16 divisors (see below), whose sum is σ = 290919780. Its totient is φ = 51719040.

The previous prime is 129297617. The next prime is 129297667. The reversal of 129297640 is 46792921.

It can be written as a sum of positive squares in 2 ways, for example, as 125305636 + 3992004 = 11194^2 + 1998^2 .

It is a Harshad number since it is a multiple of its sum of digits (40), and also a Moran number because the ratio is a prime number: 3232441 = 129297640 / (1 + 2 + 9 + 2 + 9 + 7 + 6 + 4 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 129297593 and 129297602.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1616181 + ... + 1616260.

Almost surely, 2^129297640 is an apocalyptic number.

129297640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

129297640 is an abundant number, since it is smaller than the sum of its proper divisors (161622140).

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

129297640 is a wasteful number, since it uses less digits than its factorization.

129297640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3232452 (or 3232448 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 129297640 is about 11370.9120126751. The cubic root of 129297640 is about 505.6657428832.

The spelling of 129297640 in words is "one hundred twenty-nine million, two hundred ninety-seven thousand, six hundred forty".