129891809920 has 32 divisors (see below), whose sum is σ = 310522609620. Its totient is φ = 51956723712.

The previous prime is 129891809911. The next prime is 129891809921. The reversal of 129891809920 is 29908198921.

It can be written as a sum of positive squares in 2 ways, for example, as 122002106944 + 7889702976 = 349288^2 + 88824^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (129891809921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 101477337 + ... + 101478616.

Almost surely, 2^129891809920 is an apocalyptic number.

129891809920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

129891809920 is an abundant number, since it is smaller than the sum of its proper divisors (180630799700).

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

129891809920 is an equidigital number, since it uses as much as digits as its factorization.

129891809920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202955972 (or 202955960 counting only the distinct ones).

The product of its (nonzero) digits is 1679616, while the sum is 58.

The spelling of 129891809920 in words is "one hundred twenty-nine billion, eight hundred ninety-one million, eight hundred nine thousand, nine hundred twenty".