129681820 has 48 divisors (see below), whose sum is σ = 286207488. Its totient is φ = 49262400.

The previous prime is 129681817. The next prime is 129681829. The reversal of 129681820 is 28186921.

It is a self number, because there is not a number n which added to its sum of digits gives 129681820.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129681829) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68527 + ... + 70393.

It is an arithmetic number, because the mean of its divisors is an integer number (5962656).

Almost surely, 2^129681820 is an apocalyptic number.

129681820 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 129681820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (143103744).

129681820 is an abundant number, since it is smaller than the sum of its proper divisors (156525668).

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

129681820 is a wasteful number, since it uses less digits than its factorization.

129681820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2050 (or 2048 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 37.

The square root of 129681820 is about 11387.7925868010. The cubic root of 129681820 is about 506.1660731675.

The spelling of 129681820 in words is "one hundred twenty-nine million, six hundred eighty-one thousand, eight hundred twenty".