21110331217 has 2 divisors, whose sum is σ = 21110331218. Its totient is φ = 21110331216.

The previous prime is 21110331199. The next prime is 21110331251. The reversal of 21110331217 is 71213301112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15118177936 + 5992153281 = 122956^2 + 77409^2 .

It is a cyclic number.

It is not a de Polignac number, because 21110331217 - 2⁷ = 21110331089 is a prime.

It is not a weakly prime, because it can be changed into another prime (21110331317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555165608 + 10555165609.

It is an arithmetic number, because the mean of its divisors is an integer number (10555165609).

Almost surely, 2^21110331217 is an apocalyptic number.

It is an amenable number.

21110331217 is a deficient number, since it is larger than the sum of its proper divisors (1).

21110331217 is an equidigital number, since it uses as much as digits as its factorization.

21110331217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252, while the sum is 22.

Adding to 21110331217 its reverse (71213301112), we get a palindrome (92323632329).

The spelling of 21110331217 in words is "twenty-one billion, one hundred ten million, three hundred thirty-one thousand, two hundred seventeen".