129137540 has 72 divisors (see below), whose sum is σ = 317224152. Its totient is φ = 44029440.

The previous prime is 129137539. The next prime is 129137543. The reversal of 129137540 is 45731921.

It can be written as a sum of positive squares in 4 ways, for example, as 18593344 + 110544196 = 4312^2 + 10514^2 .

It is a junction number, because it is equal to n+sod(n) for n = 129137497 and 129137506.

It is not an unprimeable number, because it can be changed into a prime (129137543) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 306530 + ... + 306950.

It is an arithmetic number, because the mean of its divisors is an integer number (4405891).

Almost surely, 2^129137540 is an apocalyptic number.

129137540 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 129137540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (158612076).

129137540 is an abundant number, since it is smaller than the sum of its proper divisors (188086612).

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

129137540 is a wasteful number, since it uses less digits than its factorization.

129137540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 757 (or 748 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 32.

The square root of 129137540 is about 11363.8699394176. The cubic root of 129137540 is about 505.4569467987.

The spelling of 129137540 in words is "one hundred twenty-nine million, one hundred thirty-seven thousand, five hundred forty".