21224207 has 2 divisors, whose sum is σ = 21224208. Its totient is φ = 21224206.

The previous prime is 21224191. The next prime is 21224249. The reversal of 21224207 is 70242212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21224207 - 2⁴ = 21224191 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21224267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10612103 + 10612104.

It is an arithmetic number, because the mean of its divisors is an integer number (10612104).

Almost surely, 2^21224207 is an apocalyptic number.

21224207 is a deficient number, since it is larger than the sum of its proper divisors (1).

21224207 is an equidigital number, since it uses as much as digits as its factorization.

21224207 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 20.

The square root of 21224207 is about 4606.9737355448. The cubic root of 21224207 is about 276.8708012653.

Adding to 21224207 its reverse (70242212), we get a palindrome (91466419).

The spelling of 21224207 in words is "twenty-one million, two hundred twenty-four thousand, two hundred seven".