8217659521 has 4 divisors (see below), whose sum is σ = 8482745344. Its totient is φ = 7952573700.

The previous prime is 8217659491. The next prime is 8217659531. The reversal of 8217659521 is 1259567128.

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.

It is a cyclic number.

It is not a de Polignac number, because 8217659521 - 2²⁵ = 8184105089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8217659531) 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, 132542865 + ... + 132542926.

It is an arithmetic number, because the mean of its divisors is an integer number (2120686336).

Almost surely, 2^8217659521 is an apocalyptic number.

It is an amenable number.

8217659521 is a deficient number, since it is larger than the sum of its proper divisors (265085823).

8217659521 is a wasteful number, since it uses less digits than its factorization.

8217659521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265085822.

The product of its digits is 302400, while the sum is 46.

The square root of 8217659521 is about 90651.3073319960. The cubic root of 8217659521 is about 2017.9762367943.

The spelling of 8217659521 in words is "eight billion, two hundred seventeen million, six hundred fifty-nine thousand, five hundred twenty-one".