172724509 has 4 divisors (see below), whose sum is σ = 175983516. Its totient is φ = 169465504.

The previous prime is 172724491. The next prime is 172724533. The reversal of 172724509 is 905427271.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 905427271 = 7 ⋅129346753.

It can be written as a sum of positive squares in 2 ways, for example, as 100100025 + 72624484 = 10005^2 + 8522^2 .

It is a cyclic number.

It is not a de Polignac number, because 172724509 - 2⁵ = 172724477 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 (172724599) 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 in 3 ways as a sum of consecutive naturals, for example, 1629424 + ... + 1629529.

It is an arithmetic number, because the mean of its divisors is an integer number (43995879).

Almost surely, 2^172724509 is an apocalyptic number.

It is an amenable number.

172724509 is a deficient number, since it is larger than the sum of its proper divisors (3259007).

172724509 is an equidigital number, since it uses as much as digits as its factorization.

172724509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3259006.

The product of its (nonzero) digits is 35280, while the sum is 37.

The square root of 172724509 is about 13142.4696689777. The cubic root of 172724509 is about 556.9095375287.

The spelling of 172724509 in words is "one hundred seventy-two million, seven hundred twenty-four thousand, five hundred nine".