129138840 has 128 divisors (see below), whose sum is σ = 434808000. Its totient is φ = 34089984.

The previous prime is 129138833. The next prime is 129138853. The reversal of 129138840 is 48831921.

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 = 129138795 and 129138804.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 117172 + ... + 118268.

Almost surely, 2^129138840 is an apocalyptic number.

129138840 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 129138840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (217404000).

129138840 is an abundant number, since it is smaller than the sum of its proper divisors (305669160).

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

129138840 is a wasteful number, since it uses less digits than its factorization.

129138840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1226 (or 1216 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 129138840 is about 11363.9271380980. The cubic root of 129138840 is about 505.4586429020.

The spelling of 129138840 in words is "one hundred twenty-nine million, one hundred thirty-eight thousand, eight hundred forty".