21767071872017 has 2 divisors, whose sum is σ = 21767071872018. Its totient is φ = 21767071872016.

The previous prime is 21767071871933. The next prime is 21767071872107. The reversal of 21767071872017 is 71027817076712.

It is a happy number.

Together with next prime (21767071872107) 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., 21526250050321 + 240821821696 = 4639639^2 + 490736^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21767071872017 is a prime.

It is not a weakly prime, because it can be changed into another prime (21767071872817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10883535936008 + 10883535936009.

It is an arithmetic number, because the mean of its divisors is an integer number (10883535936009).

Almost surely, 2^{21767071872017} is an apocalyptic number.

It is an amenable number.

21767071872017 is a deficient number, since it is larger than the sum of its proper divisors (1).

21767071872017 is an equidigital number, since it uses as much as digits as its factorization.

21767071872017 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3226944, while the sum is 56.

The spelling of 21767071872017 in words is "twenty-one trillion, seven hundred sixty-seven billion, seventy-one million, eight hundred seventy-two thousand, seventeen".