21300663 has 4 divisors (see below), whose sum is σ = 28400888. Its totient is φ = 14200440.

The previous prime is 21300659. The next prime is 21300673. The reversal of 21300663 is 36600312.

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

It is not a de Polignac number, because 21300663 - 2² = 21300659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21300673) 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, 3550108 + ... + 3550113.

It is an arithmetic number, because the mean of its divisors is an integer number (7100222).

Almost surely, 2^21300663 is an apocalyptic number.

21300663 is a deficient number, since it is larger than the sum of its proper divisors (7100225).

21300663 is an equidigital number, since it uses as much as digits as its factorization.

21300663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7100224.

The product of its (nonzero) digits is 648, while the sum is 21.

The square root of 21300663 is about 4615.2641311197. The cubic root of 21300663 is about 277.2028602575.

Adding to 21300663 its reverse (36600312), we get a palindrome (57900975).

The spelling of 21300663 in words is "twenty-one million, three hundred thousand, six hundred sixty-three".