21818363 has 8 divisors (see below), whose sum is σ = 24971232. Its totient is φ = 18674496.

The previous prime is 21818359. The next prime is 21818393. The reversal of 21818363 is 36381812.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21818363 - 2² = 21818359 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21818393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4181 + ... + 7817.

It is an arithmetic number, because the mean of its divisors is an integer number (3121404).

Almost surely, 2^21818363 is an apocalyptic number.

21818363 is a deficient number, since it is larger than the sum of its proper divisors (3152869).

21818363 is an equidigital number, since it uses as much as digits as its factorization.

21818363 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4501.

The product of its digits is 6912, while the sum is 32.

The square root of 21818363 is about 4671.0130592838. The cubic root of 21818363 is about 279.4306585835.

It can be divided in two parts, 218 and 18363, that added together give a palindrome (18581).

The spelling of 21818363 in words is "twenty-one million, eight hundred eighteen thousand, three hundred sixty-three".