129394199821 has 2 divisors, whose sum is σ = 129394199822. Its totient is φ = 129394199820.

The previous prime is 129394199719. The next prime is 129394199827. The reversal of 129394199821 is 128991493921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 129394161796 + 38025 = 359714^2 + 195^2 .

It is a cyclic number.

It is not a de Polignac number, because 129394199821 - 2⁹ = 129394199309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129394199827) 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 as a sum of consecutive naturals, namely, 64697099910 + 64697099911.

It is an arithmetic number, because the mean of its divisors is an integer number (64697099911).

Almost surely, 2^129394199821 is an apocalyptic number.

It is an amenable number.

129394199821 is a deficient number, since it is larger than the sum of its proper divisors (1).

129394199821 is an equidigital number, since it uses as much as digits as its factorization.

129394199821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2519424, while the sum is 58.

The spelling of 129394199821 in words is "one hundred twenty-nine billion, three hundred ninety-four million, one hundred ninety-nine thousand, eight hundred twenty-one".