21064249 has 2 divisors, whose sum is σ = 21064250. Its totient is φ = 21064248.

The previous prime is 21064247. The next prime is 21064259. The reversal of 21064249 is 94246012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16548624 + 4515625 = 4068^2 + 2125^2 .

It is a cyclic number.

It is not a de Polignac number, because 21064249 - 2¹ = 21064247 is a prime.

Together with 21064247, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21064247) 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, 10532124 + 10532125.

It is an arithmetic number, because the mean of its divisors is an integer number (10532125).

Almost surely, 2^21064249 is an apocalyptic number.

It is an amenable number.

21064249 is a deficient number, since it is larger than the sum of its proper divisors (1).

21064249 is an equidigital number, since it uses as much as digits as its factorization.

21064249 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 21064249 is about 4589.5804819177. The cubic root of 21064249 is about 276.1734932789.

The spelling of 21064249 in words is "twenty-one million, sixty-four thousand, two hundred forty-nine".