12171220717 has 2 divisors, whose sum is σ = 12171220718. Its totient is φ = 12171220716.

The previous prime is 12171220709. The next prime is 12171220727. The reversal of 12171220717 is 71702217121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9090859716 + 3080361001 = 95346^2 + 55501^2 .

It is a cyclic number.

It is not a de Polignac number, because 12171220717 - 2³ = 12171220709 is a prime.

It is a super-2 number, since 2×12171220717² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12171220727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6085610358 + 6085610359.

It is an arithmetic number, because the mean of its divisors is an integer number (6085610359).

Almost surely, 2^12171220717 is an apocalyptic number.

It is an amenable number.

12171220717 is a deficient number, since it is larger than the sum of its proper divisors (1).

12171220717 is an equidigital number, since it uses as much as digits as its factorization.

12171220717 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2744, while the sum is 31.

Adding to 12171220717 its reverse (71702217121), we get a palindrome (83873437838).

The spelling of 12171220717 in words is "twelve billion, one hundred seventy-one million, two hundred twenty thousand, seven hundred seventeen".