21221333317 has 2 divisors, whose sum is σ = 21221333318. Its totient is φ = 21221333316.

The previous prime is 21221333303. The next prime is 21221333333. The reversal of 21221333317 is 71333312212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20842408161 + 378925156 = 144369^2 + 19466^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221333317 - 2¹¹ = 21221331269 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221333347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610666658 + 10610666659.

It is an arithmetic number, because the mean of its divisors is an integer number (10610666659).

Almost surely, 2^21221333317 is an apocalyptic number.

It is an amenable number.

21221333317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221333317 is an equidigital number, since it uses as much as digits as its factorization.

21221333317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 28.

Adding to 21221333317 its reverse (71333312212), we get a palindrome (92554645529).

The spelling of 21221333317 in words is "twenty-one billion, two hundred twenty-one million, three hundred thirty-three thousand, three hundred seventeen".