21311017317 has 12 divisors (see below), whose sum is σ = 31614542700. Its totient is φ = 13823362368.

The previous prime is 21311017313. The next prime is 21311017373. The reversal of 21311017317 is 71371011312.

21311017317 is a `hidden beast` number, since 21 + 311 + 0 + 17 + 317 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 12520267236 + 8790750081 = 111894^2 + 93759^2 .

It is not a de Polignac number, because 21311017317 - 2² = 21311017313 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311017313) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 31998192 + ... + 31998857.

It is an arithmetic number, because the mean of its divisors is an integer number (2634545225).

Almost surely, 2^21311017317 is an apocalyptic number.

It is an amenable number.

21311017317 is a deficient number, since it is larger than the sum of its proper divisors (10303525383).

21311017317 is a wasteful number, since it uses less digits than its factorization.

21311017317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63997092 (or 63997089 counting only the distinct ones).

The product of its (nonzero) digits is 882, while the sum is 27.

Adding to 21311017317 its reverse (71371011312), we get a palindrome (92682028629).

The spelling of 21311017317 in words is "twenty-one billion, three hundred eleven million, seventeen thousand, three hundred seventeen".