21200663 has 4 divisors (see below), whose sum is σ = 23128008. Its totient is φ = 19273320.

The previous prime is 21200639. The next prime is 21200681. The reversal of 21200663 is 36600212.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21200663 - 2¹⁰ = 21199639 is a prime.

It is a super-2 number, since 2×21200663² = 898936223279138, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 963656 + ... + 963677.

It is an arithmetic number, because the mean of its divisors is an integer number (5782002).

Almost surely, 2^21200663 is an apocalyptic number.

21200663 is a deficient number, since it is larger than the sum of its proper divisors (1927345).

21200663 is a wasteful number, since it uses less digits than its factorization.

21200663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1927344.

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 21200663 is about 4604.4177699249. The cubic root of 21200663 is about 276.7683858486.

Adding to 21200663 its reverse (36600212), we get a palindrome (57800875).

The spelling of 21200663 in words is "twenty-one million, two hundred thousand, six hundred sixty-three".