172105809 has 8 divisors (see below), whose sum is σ = 230006112. Its totient is φ = 114471360.

The previous prime is 172105799. The next prime is 172105853. The reversal of 172105809 is 908501271.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 172105809 - 2⁵ = 172105777 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 172105809.

It is not an unprimeable number, because it can be changed into a prime (172105859) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 64947 + ... + 67544.

It is an arithmetic number, because the mean of its divisors is an integer number (28750764).

Almost surely, 2^172105809 is an apocalyptic number.

It is an amenable number.

172105809 is a deficient number, since it is larger than the sum of its proper divisors (57900303).

172105809 is a wasteful number, since it uses less digits than its factorization.

172105809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132927.

The product of its (nonzero) digits is 5040, while the sum is 33.

The square root of 172105809 is about 13118.9103587150. The cubic root of 172105809 is about 556.2437911355.

The spelling of 172105809 in words is "one hundred seventy-two million, one hundred five thousand, eight hundred nine".