21241249 has 2 divisors, whose sum is σ = 21241250. Its totient is φ = 21241248.

The previous prime is 21241247. The next prime is 21241261. The reversal of 21241249 is 94214212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21022225 + 219024 = 4585^2 + 468^2 .

It is a cyclic number.

It is not a de Polignac number, because 21241249 - 2¹ = 21241247 is a prime.

Together with 21241247, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21241247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10620624 + 10620625.

It is an arithmetic number, because the mean of its divisors is an integer number (10620625).

Almost surely, 2^21241249 is an apocalyptic number.

It is an amenable number.

21241249 is a deficient number, since it is larger than the sum of its proper divisors (1).

21241249 is an equidigital number, since it uses as much as digits as its factorization.

21241249 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 25.

The square root of 21241249 is about 4608.8229516873. The cubic root of 21241249 is about 276.9448860099.

The spelling of 21241249 in words is "twenty-one million, two hundred forty-one thousand, two hundred forty-nine".