129000000000121 has 4 divisors (see below), whose sum is σ = 129001344000100. Its totient is φ = 128998656000144.

The previous prime is 129000000000103. The next prime is 129000000000133. The reversal of 129000000000121 is 121000000000921.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18557451002896 + 110442548997225 = 4307836^2 + 10509165^2 .

It is a cyclic number.

It is not a de Polignac number, because 129000000000121 - 2⁵ = 129000000000089 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 129000000000095 and 129000000000104.

It is not an unprimeable number, because it can be changed into a prime (129000000000821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 671856006 + ... + 672047983.

It is an arithmetic number, because the mean of its divisors is an integer number (32250336000025).

Almost surely, 2^{129000000000121} is an apocalyptic number.

It is an amenable number.

129000000000121 is a deficient number, since it is larger than the sum of its proper divisors (1343999979).

129000000000121 is an equidigital number, since it uses as much as digits as its factorization.

129000000000121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1343999978.

The product of its (nonzero) digits is 36, while the sum is 16.

The spelling of 129000000000121 in words is "one hundred twenty-nine trillion, one hundred twenty-one", and thus it is an aban number.