12921817 has 2 divisors, whose sum is σ = 12921818. Its totient is φ = 12921816.

The previous prime is 12921809. The next prime is 12921829. The reversal of 12921817 is 71812921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11128896 + 1792921 = 3336^2 + 1339^2 .

It is a cyclic number.

It is not a de Polignac number, because 12921817 - 2³ = 12921809 is a prime.

It is not a weakly prime, because it can be changed into another prime (12921217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6460908 + 6460909.

It is an arithmetic number, because the mean of its divisors is an integer number (6460909).

Almost surely, 2^12921817 is an apocalyptic number.

It is an amenable number.

12921817 is a deficient number, since it is larger than the sum of its proper divisors (1).

12921817 is an equidigital number, since it uses as much as digits as its factorization.

12921817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2016, while the sum is 31.

The square root of 12921817 is about 3594.6928936976. The cubic root of 12921817 is about 234.6611503937.

The spelling of 12921817 in words is "twelve million, nine hundred twenty-one thousand, eight hundred seventeen".