21244263 has 8 divisors (see below), whose sum is σ = 28388976. Its totient is φ = 14131200.

The previous prime is 21244259. The next prime is 21244277. The reversal of 21244263 is 36244212.

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

It is not a de Polignac number, because 21244263 - 2² = 21244259 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21244213) 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 in 7 ways as a sum of consecutive naturals, for example, 6298 + ... + 9063.

It is an arithmetic number, because the mean of its divisors is an integer number (3548622).

Almost surely, 2^21244263 is an apocalyptic number.

21244263 is a deficient number, since it is larger than the sum of its proper divisors (7144713).

21244263 is a wasteful number, since it uses less digits than its factorization.

21244263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15825.

The product of its digits is 2304, while the sum is 24.

The square root of 21244263 is about 4609.1499216233. The cubic root of 21244263 is about 276.9579843045.

Adding to 21244263 its reverse (36244212), we get a palindrome (57488475).

The spelling of 21244263 in words is "twenty-one million, two hundred forty-four thousand, two hundred sixty-three".