129391490921 has 32 divisors (see below), whose sum is σ = 169168262400. Its totient is φ = 96014177280.

The previous prime is 129391490909. The next prime is 129391490999. The reversal of 129391490921 is 129094193921.

It is not a de Polignac number, because 129391490921 - 2³⁰ = 128317749097 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 129391490921.

It is not an unprimeable number, because it can be changed into a prime (129391495921) 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 31 ways as a sum of consecutive naturals, for example, 233876 + ... + 559893.

It is an arithmetic number, because the mean of its divisors is an integer number (5286508200).

Almost surely, 2^129391490921 is an apocalyptic number.

129391490921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

129391490921 is a deficient number, since it is larger than the sum of its proper divisors (39776771479).

129391490921 is a wasteful number, since it uses less digits than its factorization.

129391490921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 793889.

The product of its (nonzero) digits is 314928, while the sum is 50.

The spelling of 129391490921 in words is "one hundred twenty-nine billion, three hundred ninety-one million, four hundred ninety thousand, nine hundred twenty-one".