172521617 has 2 divisors, whose sum is σ = 172521618. Its totient is φ = 172521616.

The previous prime is 172521571. The next prime is 172521649. The reversal of 172521617 is 716125271.

It is an a-pointer prime, because the next prime (172521649) can be obtained adding 172521617 to its sum of digits (32).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 168065296 + 4456321 = 12964^2 + 2111^2 .

It is a cyclic number.

It is not a de Polignac number, because 172521617 - 2²⁴ = 155744401 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (172521697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86260808 + 86260809.

It is an arithmetic number, because the mean of its divisors is an integer number (86260809).

Almost surely, 2^172521617 is an apocalyptic number.

It is an amenable number.

172521617 is a deficient number, since it is larger than the sum of its proper divisors (1).

172521617 is an equidigital number, since it uses as much as digits as its factorization.

172521617 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5880, while the sum is 32.

The square root of 172521617 is about 13134.7484559089. The cubic root of 172521617 is about 556.6913929200.

Adding to 172521617 its reverse (716125271), we get a palindrome (888646888).

The spelling of 172521617 in words is "one hundred seventy-two million, five hundred twenty-one thousand, six hundred seventeen".