21363221 has 4 divisors (see below), whose sum is σ = 23305344. Its totient is φ = 19421100.

The previous prime is 21363193. The next prime is 21363253. The reversal of 21363221 is 12236312.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21363221 - 2¹⁰ = 21362197 is a prime.

It is a super-2 number, since 2×21363221² = 912774422989682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21363193 and 21363202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21363421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 971045 + ... + 971066.

It is an arithmetic number, because the mean of its divisors is an integer number (5826336).

Almost surely, 2^21363221 is an apocalyptic number.

It is an amenable number.

21363221 is a deficient number, since it is larger than the sum of its proper divisors (1942123).

21363221 is a wasteful number, since it uses less digits than its factorization.

21363221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1942122.

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

The square root of 21363221 is about 4622.0364559358. The cubic root of 21363221 is about 277.4739677444.

Adding to 21363221 its reverse (12236312), we get a palindrome (33599533).

The spelling of 21363221 in words is "twenty-one million, three hundred sixty-three thousand, two hundred twenty-one".