21226215 has 8 divisors (see below), whose sum is σ = 33961968. Its totient is φ = 11320640.

The previous prime is 21226213. The next prime is 21226237. The reversal of 21226215 is 51262212.

It is a happy number.

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

It is not a de Polignac number, because 21226215 - 2¹ = 21226213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21226191 and 21226200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21226213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 707526 + ... + 707555.

It is an arithmetic number, because the mean of its divisors is an integer number (4245246).

Almost surely, 2^21226215 is an apocalyptic number.

21226215 is a deficient number, since it is larger than the sum of its proper divisors (12735753).

21226215 is a wasteful number, since it uses less digits than its factorization.

21226215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1415089.

The product of its digits is 480, while the sum is 21.

The square root of 21226215 is about 4607.1916608711. The cubic root of 21226215 is about 276.8795324754.

Adding to 21226215 its reverse (51262212), we get a palindrome (72488427).

The spelling of 21226215 in words is "twenty-one million, two hundred twenty-six thousand, two hundred fifteen".