129239920 has 20 divisors (see below), whose sum is σ = 300483000. Its totient is φ = 51695936.

The previous prime is 129239911. The next prime is 129239923. The reversal of 129239920 is 29932921.

It is a tau number, because it is divible by the number of its divisors (20).

It is a self number, because there is not a number n which added to its sum of digits gives 129239920.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129239923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 807670 + ... + 807829.

It is an arithmetic number, because the mean of its divisors is an integer number (15024150).

Almost surely, 2^129239920 is an apocalyptic number.

129239920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

129239920 is an abundant number, since it is smaller than the sum of its proper divisors (171243080).

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

129239920 is a wasteful number, since it uses less digits than its factorization.

129239920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1615512 (or 1615506 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 37.

The square root of 129239920 is about 11368.3736743652. The cubic root of 129239920 is about 505.5904866220.

The spelling of 129239920 in words is "one hundred twenty-nine million, two hundred thirty-nine thousand, nine hundred twenty".