21213227 has 6 divisors (see below), whose sum is σ = 24676668. Its totient is φ = 18182724.

The previous prime is 21213193. The next prime is 21213251. The reversal of 21213227 is 72231212.

It is not a de Polignac number, because 21213227 - 2⁶ = 21213163 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21213199 and 21213208.

It is not an unprimeable number, because it can be changed into a prime (21213287) 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 5 ways as a sum of consecutive naturals, for example, 216413 + ... + 216510.

It is an arithmetic number, because the mean of its divisors is an integer number (4112778).

Almost surely, 2^21213227 is an apocalyptic number.

21213227 is a deficient number, since it is larger than the sum of its proper divisors (3463441).

21213227 is an equidigital number, since it uses as much as digits as its factorization.

21213227 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 432937 (or 432930 counting only the distinct ones).

The product of its digits is 336, while the sum is 20.

The square root of 21213227 is about 4605.7819097304. The cubic root of 21213227 is about 276.8230481535.

Adding to 21213227 its reverse (72231212), we get a palindrome (93444439).

The spelling of 21213227 in words is "twenty-one million, two hundred thirteen thousand, two hundred twenty-seven".