12921397 has 2 divisors, whose sum is σ = 12921398. Its totient is φ = 12921396.

The previous prime is 12921373. The next prime is 12921407. The reversal of 12921397 is 79312921.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12859396 + 62001 = 3586^2 + 249^2 .

It is an emirp because it is prime and its reverse (79312921) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12921397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12928397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6460698 + 6460699.

It is an arithmetic number, because the mean of its divisors is an integer number (6460699).

Almost surely, 2^12921397 is an apocalyptic number.

It is an amenable number.

12921397 is a deficient number, since it is larger than the sum of its proper divisors (1).

12921397 is an equidigital number, since it uses as much as digits as its factorization.

12921397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6804, while the sum is 34.

The square root of 12921397 is about 3594.6344737678. The cubic root of 12921397 is about 234.6586079558.

The spelling of 12921397 in words is "twelve million, nine hundred twenty-one thousand, three hundred ninety-seven".