12921281 has 2 divisors, whose sum is σ = 12921282. Its totient is φ = 12921280.

The previous prime is 12921277. The next prime is 12921283. The reversal of 12921281 is 18212921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11282881 + 1638400 = 3359^2 + 1280^2 .

It is a cyclic number.

It is not a de Polignac number, because 12921281 - 2² = 12921277 is a prime.

It is a super-2 number, since 2×12921281² = 333919005361922, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 12921283, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 12921281.

It is not a weakly prime, because it can be changed into another prime (12921283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6460640 + 6460641.

It is an arithmetic number, because the mean of its divisors is an integer number (6460641).

Almost surely, 2^12921281 is an apocalyptic number.

It is an amenable number.

12921281 is a deficient number, since it is larger than the sum of its proper divisors (1).

12921281 is an equidigital number, since it uses as much as digits as its factorization.

12921281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 26.

The square root of 12921281 is about 3594.6183385723. The cubic root of 12921281 is about 234.6579057490.

The spelling of 12921281 in words is "twelve million, nine hundred twenty-one thousand, two hundred eighty-one".