21663363 has 8 divisors (see below), whose sum is σ = 30404800. Its totient is φ = 13682088.

The previous prime is 21663359. The next prime is 21663373. The reversal of 21663363 is 36336612.

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

It is not a de Polignac number, because 21663363 - 2² = 21663359 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 21663363.

It is not an unprimeable number, because it can be changed into a prime (21663373) 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, 189973 + ... + 190086.

It is an arithmetic number, because the mean of its divisors is an integer number (3800600).

Almost surely, 2^21663363 is an apocalyptic number.

21663363 is a deficient number, since it is larger than the sum of its proper divisors (8741437).

21663363 is a wasteful number, since it uses less digits than its factorization.

21663363 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380081.

The product of its digits is 11664, while the sum is 30.

The square root of 21663363 is about 4654.3917970021. The cubic root of 21663363 is about 278.7673836076.

Adding to 21663363 its reverse (36336612), we get a palindrome (57999975).

The spelling of 21663363 in words is "twenty-one million, six hundred sixty-three thousand, three hundred sixty-three".