129638020 has 24 divisors (see below), whose sum is σ = 272626200. Its totient is φ = 51781632.

The previous prime is 129638011. The next prime is 129638021. The reversal of 129638020 is 20836921.

It can be written as a sum of positive squares in 4 ways, for example, as 906304 + 128731716 = 952^2 + 11346^2 .

It is not an unprimeable number, because it can be changed into a prime (129638021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11166 + ... + 19594.

It is an arithmetic number, because the mean of its divisors is an integer number (11359425).

Almost surely, 2^129638020 is an apocalyptic number.

129638020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

129638020 is an abundant number, since it is smaller than the sum of its proper divisors (142988180).

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

129638020 is a wasteful number, since it uses less digits than its factorization.

129638020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9207 (or 9205 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 129638020 is about 11385.8693124416. The cubic root of 129638020 is about 506.1090809320.

The spelling of 129638020 in words is "one hundred twenty-nine million, six hundred thirty-eight thousand, twenty".