129238920 has 96 divisors (see below), whose sum is σ = 424471320. Its totient is φ = 34099200.

The previous prime is 129238919. The next prime is 129238927. The reversal of 129238920 is 29832921.

It can be written as a sum of positive squares in 4 ways, for example, as 95296644 + 33942276 = 9762^2 + 5826^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (129238927) 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, 33070 + ... + 36770.

Almost surely, 2^129238920 is an apocalyptic number.

129238920 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 129238920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (212235660).

129238920 is an abundant number, since it is smaller than the sum of its proper divisors (295232400).

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

129238920 is a wasteful number, since it uses less digits than its factorization.

129238920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3815 (or 3808 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 129238920 is about 11368.3296926154. The cubic root of 129238920 is about 505.5891826085.

The spelling of 129238920 in words is "one hundred twenty-nine million, two hundred thirty-eight thousand, nine hundred twenty".