21229249 has 2 divisors, whose sum is σ = 21229250. Its totient is φ = 21229248.

The previous prime is 21229237. The next prime is 21229261. The reversal of 21229249 is 94292212.

It is a balanced prime because it is at equal distance from previous prime (21229237) and next prime (21229261).

It can be written as a sum of positive squares in only one way, i.e., 18447025 + 2782224 = 4295^2 + 1668^2 .

It is a cyclic number.

It is not a de Polignac number, because 21229249 - 2⁹ = 21228737 is a prime.

It is equal to p_1343497 and since 21229249 and 1343497 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21229249.

It is not a weakly prime, because it can be changed into another prime (21229049) 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, 10614624 + 10614625.

It is an arithmetic number, because the mean of its divisors is an integer number (10614625).

Almost surely, 2^21229249 is an apocalyptic number.

It is an amenable number.

21229249 is a deficient number, since it is larger than the sum of its proper divisors (1).

21229249 is an equidigital number, since it uses as much as digits as its factorization.

21229249 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 31.

The square root of 21229249 is about 4607.5209169357. The cubic root of 21229249 is about 276.8927239069.

The spelling of 21229249 in words is "twenty-one million, two hundred twenty-nine thousand, two hundred forty-nine".