21303649 has 2 divisors, whose sum is σ = 21303650. Its totient is φ = 21303648.

The previous prime is 21303631. The next prime is 21303671. The reversal of 21303649 is 94630312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17430625 + 3873024 = 4175^2 + 1968^2 .

It is a cyclic number.

It is not a de Polignac number, because 21303649 - 2⁹ = 21303137 is a prime.

It is not a weakly prime, because it can be changed into another prime (21303629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10651824 + 10651825.

It is an arithmetic number, because the mean of its divisors is an integer number (10651825).

Almost surely, 2^21303649 is an apocalyptic number.

It is an amenable number.

21303649 is a deficient number, since it is larger than the sum of its proper divisors (1).

21303649 is an equidigital number, since it uses as much as digits as its factorization.

21303649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 21303649 is about 4615.5876115615. The cubic root of 21303649 is about 277.2158127349.

It can be divided in two parts, 21303 and 649, that added together give a cube (21952 = 28³).

The spelling of 21303649 in words is "twenty-one million, three hundred three thousand, six hundred forty-nine".