12808721 has 2 divisors, whose sum is σ = 12808722. Its totient is φ = 12808720.

The previous prime is 12808661. The next prime is 12808739. The reversal of 12808721 is 12780821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6558721 + 6250000 = 2561^2 + 2500^2 .

It is a cyclic number.

It is not a de Polignac number, because 12808721 - 2¹⁴ = 12792337 is a prime.

It is not a weakly prime, because it can be changed into another prime (12808751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6404360 + 6404361.

It is an arithmetic number, because the mean of its divisors is an integer number (6404361).

Almost surely, 2^12808721 is an apocalyptic number.

It is an amenable number.

12808721 is a deficient number, since it is larger than the sum of its proper divisors (1).

12808721 is an equidigital number, since it uses as much as digits as its factorization.

12808721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1792, while the sum is 29.

The square root of 12808721 is about 3578.9273532722. The cubic root of 12808721 is about 233.9745327435.

It can be divided in two parts, 1280 and 8721, that added together give a palindrome (10001).

The spelling of 12808721 in words is "twelve million, eight hundred eight thousand, seven hundred twenty-one".