21444663 has 8 divisors (see below), whose sum is σ = 28888048. Its totient is φ = 14148864.

The previous prime is 21444649. The next prime is 21444677. The reversal of 21444663 is 36644412.

It is an interprime number because it is at equal distance from previous prime (21444649) and next prime (21444677).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21444663 - 2²⁰ = 20396087 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21444663.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21444613) 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 in 7 ways as a sum of consecutive naturals, for example, 36556 + ... + 37137.

It is an arithmetic number, because the mean of its divisors is an integer number (3611006).

Almost surely, 2^21444663 is an apocalyptic number.

21444663 is a deficient number, since it is larger than the sum of its proper divisors (7443385).

21444663 is an equidigital number, since it uses as much as digits as its factorization.

21444663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73793.

The product of its digits is 13824, while the sum is 30.

The square root of 21444663 is about 4630.8382610495. The cubic root of 21444663 is about 277.8261209313.

The spelling of 21444663 in words is "twenty-one million, four hundred forty-four thousand, six hundred sixty-three".