21226217 has 8 divisors (see below), whose sum is σ = 23452416. Its totient is φ = 19108672.

The previous prime is 21226213. The next prime is 21226237. The reversal of 21226217 is 71262212.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21226217 - 2² = 21226213 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21226192 and 21226201.

It is not an unprimeable number, because it can be changed into a prime (21226213) 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 7 ways as a sum of consecutive naturals, for example, 26753 + ... + 27534.

It is an arithmetic number, because the mean of its divisors is an integer number (2931552).

Almost surely, 2^21226217 is an apocalyptic number.

It is an amenable number.

21226217 is a deficient number, since it is larger than the sum of its proper divisors (2226199).

21226217 is a wasteful number, since it uses less digits than its factorization.

21226217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54327.

The product of its digits is 672, while the sum is 23.

The square root of 21226217 is about 4607.1918779230. The cubic root of 21226217 is about 276.8795411716.

Adding to 21226217 its reverse (71262212), we get a palindrome (92488429).

The spelling of 21226217 in words is "twenty-one million, two hundred twenty-six thousand, two hundred seventeen".