817172172905 has 16 divisors (see below), whose sum is σ = 1089936679104. Its totient is φ = 583093692480.

The previous prime is 817172172871. The next prime is 817172173033. The reversal of 817172172905 is 509271271718.

It is not a de Polignac number, because 817172172905 - 2⁶ = 817172172841 is a prime.

It is a super-2 number, since 2×817172172905² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 140163839 + ... + 140169668.

It is an arithmetic number, because the mean of its divisors is an integer number (68121042444).

Almost surely, 2^817172172905 is an apocalyptic number.

It is an amenable number.

817172172905 is a deficient number, since it is larger than the sum of its proper divisors (272764506199).

817172172905 is a wasteful number, since it uses less digits than its factorization.

817172172905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280333576.

The product of its (nonzero) digits is 493920, while the sum is 50.

The spelling of 817172172905 in words is "eight hundred seventeen billion, one hundred seventy-two million, one hundred seventy-two thousand, nine hundred five".