129640400 has 30 divisors (see below), whose sum is σ = 311462022. Its totient is φ = 51856000.

The previous prime is 129640393. The next prime is 129640409. The reversal of 129640400 is 4046921.

It can be written as a sum of positive squares in 3 ways, for example, as 44944 + 129595456 = 212^2 + 11384^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 129640400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129640409) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 161651 + ... + 162450.

Almost surely, 2^129640400 is an apocalyptic number.

129640400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

129640400 is an abundant number, since it is smaller than the sum of its proper divisors (181821622).

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

129640400 is a wasteful number, since it uses less digits than its factorization.

129640400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324119 (or 324108 counting only the distinct ones).

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

The square root of 129640400 is about 11385.9738274774. The cubic root of 129640400 is about 506.1121781002.

The spelling of 129640400 in words is "one hundred twenty-nine million, six hundred forty thousand, four hundred".