172021107217 has 2 divisors, whose sum is σ = 172021107218. Its totient is φ = 172021107216.

The previous prime is 172021107199. The next prime is 172021107229. The reversal of 172021107217 is 712701120271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 165473222656 + 6547884561 = 406784^2 + 80919^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172021107217 is a prime.

It is a super-2 number, since 2×172021107217² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (172021107277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86010553608 + 86010553609.

It is an arithmetic number, because the mean of its divisors is an integer number (86010553609).

Almost surely, 2^172021107217 is an apocalyptic number.

It is an amenable number.

172021107217 is a deficient number, since it is larger than the sum of its proper divisors (1).

172021107217 is an equidigital number, since it uses as much as digits as its factorization.

172021107217 is an odious number, because the sum of its binary digits is odd.

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

Adding to 172021107217 its reverse (712701120271), we get a palindrome (884722227488).

The spelling of 172021107217 in words is "one hundred seventy-two billion, twenty-one million, one hundred seven thousand, two hundred seventeen".