129121296649 has 4 divisors (see below), whose sum is σ = 129133798164. Its totient is φ = 129108795136.

The previous prime is 129121296641. The next prime is 129121296671. The reversal of 129121296649 is 946692121921.

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 51799484025 + 77321812624 = 227595^2 + 278068^2 .

It is a cyclic number.

It is not a de Polignac number, because 129121296649 - 2³ = 129121296641 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 129121296596 and 129121296605.

It is not an unprimeable number, because it can be changed into a prime (129121296641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6235252 + ... + 6255925.

It is an arithmetic number, because the mean of its divisors is an integer number (32283449541).

Almost surely, 2^129121296649 is an apocalyptic number.

It is an amenable number.

129121296649 is a deficient number, since it is larger than the sum of its proper divisors (12501515).

129121296649 is a wasteful number, since it uses less digits than its factorization.

129121296649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12501514.

The product of its digits is 839808, while the sum is 52.

The spelling of 129121296649 in words is "one hundred twenty-nine billion, one hundred twenty-one million, two hundred ninety-six thousand, six hundred forty-nine".