129991199921 has 8 divisors (see below), whose sum is σ = 143925128544. Its totient is φ = 116410029120.

The previous prime is 129991199867. The next prime is 129991199929.

129991199921 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 129991199921 - 2⁶ = 129991199857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129991199929) 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, 88188680 + ... + 88190153.

It is an arithmetic number, because the mean of its divisors is an integer number (17990641068).

Almost surely, 2^129991199921 is an apocalyptic number.

129991199921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

129991199921 is a deficient number, since it is larger than the sum of its proper divisors (13933928623).

129991199921 is a wasteful number, since it uses less digits than its factorization.

129991199921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176378911.

The product of its digits is 2125764, while the sum is 62.

The spelling of 129991199921 in words is "one hundred twenty-nine billion, nine hundred ninety-one million, one hundred ninety-nine thousand, nine hundred twenty-one".