172009517 has 4 divisors (see below), whose sum is σ = 172037856. Its totient is φ = 171981180.

The previous prime is 172009501. The next prime is 172009543. The reversal of 172009517 is 715900271.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 715900271 = 953 ⋅751207.

It is a cyclic number.

It is not a de Polignac number, because 172009517 - 2⁴ = 172009501 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172002517) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 959 + ... + 18572.

It is an arithmetic number, because the mean of its divisors is an integer number (43009464).

Almost surely, 2^172009517 is an apocalyptic number.

It is an amenable number.

172009517 is a deficient number, since it is larger than the sum of its proper divisors (28339).

172009517 is an equidigital number, since it uses as much as digits as its factorization.

172009517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28338.

The product of its (nonzero) digits is 4410, while the sum is 32.

The square root of 172009517 is about 13115.2398758086. The cubic root of 172009517 is about 556.1400336085.

Adding to 172009517 its reverse (715900271), we get a palindrome (887909788).

The spelling of 172009517 in words is "one hundred seventy-two million, nine thousand, five hundred seventeen".