21423303217 has 2 divisors, whose sum is σ = 21423303218. Its totient is φ = 21423303216.

The previous prime is 21423303199. The next prime is 21423303271. The reversal of 21423303217 is 71230332412.

Together with next prime (21423303271) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17634777616 + 3788525601 = 132796^2 + 61551^2 .

It is a cyclic number.

It is not a de Polignac number, because 21423303217 - 2¹¹ = 21423301169 is a prime.

It is not a weakly prime, because it can be changed into another prime (21423303017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711651608 + 10711651609.

It is an arithmetic number, because the mean of its divisors is an integer number (10711651609).

Almost surely, 2^21423303217 is an apocalyptic number.

It is an amenable number.

21423303217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21423303217 is an equidigital number, since it uses as much as digits as its factorization.

21423303217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 28.

Adding to 21423303217 its reverse (71230332412), we get a palindrome (92653635629).

The spelling of 21423303217 in words is "twenty-one billion, four hundred twenty-three million, three hundred three thousand, two hundred seventeen".