12800000021 has 2 divisors, whose sum is σ = 12800000022. Its totient is φ = 12800000020.

The previous prime is 12799999981. The next prime is 12800000029. The reversal of 12800000021 is 12000000821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10311387025 + 2488612996 = 101545^2 + 49886^2 .

It is an emirp because it is prime and its reverse (12000000821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12800000021 - 2⁶ = 12799999957 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12799999951 and 12800000005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12800000029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6400000010 + 6400000011.

It is an arithmetic number, because the mean of its divisors is an integer number (6400000011).

Almost surely, 2^12800000021 is an apocalyptic number.

It is an amenable number.

12800000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

12800000021 is an equidigital number, since it uses as much as digits as its factorization.

12800000021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 12800000021 its reverse (12000000821), we get a palindrome (24800000842).

The spelling of 12800000021 in words is "twelve billion, eight hundred million, twenty-one", and thus it is an aban number.