21021440317 has 2 divisors, whose sum is σ = 21021440318. Its totient is φ = 21021440316.

The previous prime is 21021440309. The next prime is 21021440371. The reversal of 21021440317 is 71304412012.

Together with next prime (21021440371) 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., 14462708121 + 6558732196 = 120261^2 + 80986^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021440317 - 2³ = 21021440309 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21021440291 and 21021440300.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21021440417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510720158 + 10510720159.

It is an arithmetic number, because the mean of its divisors is an integer number (10510720159).

Almost surely, 2^21021440317 is an apocalyptic number.

It is an amenable number.

21021440317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021440317 is an equidigital number, since it uses as much as digits as its factorization.

21021440317 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1344, while the sum is 25.

Adding to 21021440317 its reverse (71304412012), we get a palindrome (92325852329).

The spelling of 21021440317 in words is "twenty-one billion, twenty-one million, four hundred forty thousand, three hundred seventeen".