21023321317 has 2 divisors, whose sum is σ = 21023321318. Its totient is φ = 21023321316.

The previous prime is 21023321309. The next prime is 21023321321. The reversal of 21023321317 is 71312332012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14227956961 + 6795364356 = 119281^2 + 82434^2 .

It is a cyclic number.

It is not a de Polignac number, because 21023321317 - 2³ = 21023321309 is a prime.

It is a super-3 number, since 3×21023321317³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 21023321291 and 21023321300.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21023321617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511660658 + 10511660659.

It is an arithmetic number, because the mean of its divisors is an integer number (10511660659).

Almost surely, 2^21023321317 is an apocalyptic number.

It is an amenable number.

21023321317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21023321317 is an equidigital number, since it uses as much as digits as its factorization.

21023321317 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 25.

Adding to 21023321317 its reverse (71312332012), we get a palindrome (92335653329).

The spelling of 21023321317 in words is "twenty-one billion, twenty-three million, three hundred twenty-one thousand, three hundred seventeen".