21010217 has 2 divisors, whose sum is σ = 21010218. Its totient is φ = 21010216.

The previous prime is 21010193. The next prime is 21010229. The reversal of 21010217 is 71201012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20286016 + 724201 = 4504^2 + 851^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010217 - 2⁶ = 21010153 is a prime.

It is not a weakly prime, because it can be changed into another prime (21010237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505108 + 10505109.

It is an arithmetic number, because the mean of its divisors is an integer number (10505109).

Almost surely, 2^21010217 is an apocalyptic number.

It is an amenable number.

21010217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010217 is an equidigital number, since it uses as much as digits as its factorization.

21010217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28, while the sum is 14.

The square root of 21010217 is about 4583.6903254910. The cubic root of 21010217 is about 275.9371531273.

Adding to 21010217 its reverse (71201012), we get a palindrome (92211229).

The spelling of 21010217 in words is "twenty-one million, ten thousand, two hundred seventeen".