217728594873 has 24 divisors (see below), whose sum is σ = 315993048800. Its totient is φ = 144462579840.

The previous prime is 217728594869. The next prime is 217728594887. The reversal of 217728594873 is 378495827712.

217728594873 is a `hidden beast` number, since 2 + 1 + 7 + 72 + 85 + 9 + 487 + 3 = 666.

It is not a de Polignac number, because 217728594873 - 2² = 217728594869 is a prime.

It is a super-2 number, since 2×217728594873² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (63) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 217728594873.

It is not an unprimeable number, because it can be changed into a prime (217728596873) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3655590 + ... + 3714672.

Almost surely, 2^217728594873 is an apocalyptic number.

It is an amenable number.

217728594873 is a deficient number, since it is larger than the sum of its proper divisors (98264453927).

217728594873 is a wasteful number, since it uses less digits than its factorization.

217728594873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61029 (or 61026 counting only the distinct ones).

The product of its digits is 47416320, while the sum is 63.

The spelling of 217728594873 in words is "two hundred seventeen billion, seven hundred twenty-eight million, five hundred ninety-four thousand, eight hundred seventy-three".