129987918 has 48 divisors (see below), whose sum is σ = 292902480. Its totient is φ = 41612928.

The previous prime is 129987901. The next prime is 129987941. The reversal of 129987918 is 819789921.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 117946 + ... + 119042.

It is an arithmetic number, because the mean of its divisors is an integer number (6102135).

Almost surely, 2^129987918 is an apocalyptic number.

129987918 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 129987918, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (146451240).

129987918 is an abundant number, since it is smaller than the sum of its proper divisors (162914562).

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

129987918 is a wasteful number, since it uses less digits than its factorization.

129987918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1361 (or 1358 counting only the distinct ones).

The product of its digits is 653184, while the sum is 54.

The square root of 129987918 is about 11401.2244079309. The cubic root of 129987918 is about 506.5640078445.

The spelling of 129987918 in words is "one hundred twenty-nine million, nine hundred eighty-seven thousand, nine hundred eighteen".