129940020 has 144 divisors (see below), whose sum is σ = 453293568. Its totient is φ = 29514240.

The previous prime is 129939991. The next prime is 129940043. The reversal of 129940020 is 20049921.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 353877 + ... + 354243.

It is an arithmetic number, because the mean of its divisors is an integer number (3147872).

Almost surely, 2^129940020 is an apocalyptic number.

129940020 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 129940020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (226646784).

129940020 is an abundant number, since it is smaller than the sum of its proper divisors (323353548).

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

129940020 is a wasteful number, since it uses less digits than its factorization.

129940020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 670 (or 665 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 129940020 is about 11399.1236505268. The cubic root of 129940020 is about 506.5017805646.

Adding to 129940020 its reverse (20049921), we get a palindrome (149989941).

The spelling of 129940020 in words is "one hundred twenty-nine million, nine hundred forty thousand, twenty".