21323315017 has 2 divisors, whose sum is σ = 21323315018. Its totient is φ = 21323315016.

The previous prime is 21323314993. The next prime is 21323315023. The reversal of 21323315017 is 71051332312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16144497721 + 5178817296 = 127061^2 + 71964^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21323315017 is a prime.

It is not a weakly prime, because it can be changed into another prime (21323315087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10661657508 + 10661657509.

It is an arithmetic number, because the mean of its divisors is an integer number (10661657509).

Almost surely, 2^21323315017 is an apocalyptic number.

It is an amenable number.

21323315017 is a deficient number, since it is larger than the sum of its proper divisors (1).

21323315017 is an equidigital number, since it uses as much as digits as its factorization.

21323315017 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3780, while the sum is 28.

Adding to 21323315017 its reverse (71051332312), we get a palindrome (92374647329).

The spelling of 21323315017 in words is "twenty-one billion, three hundred twenty-three million, three hundred fifteen thousand, seventeen".