8217256128 has 56 divisors (see below), whose sum is σ = 21780806832. Its totient is φ = 2734132224.

The previous prime is 8217256123. The next prime is 8217256129. The reversal of 8217256128 is 8216527128.

It is a self number, because there is not a number n which added to its sum of digits gives 8217256128.

It is not an unprimeable number, because it can be changed into a prime (8217256123) 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, 68526 + ... + 145362.

Almost surely, 2^8217256128 is an apocalyptic number.

It is an amenable number.

8217256128 is an abundant number, since it is smaller than the sum of its proper divisors (13563550704).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

8217256128 is a wasteful number, since it uses less digits than its factorization.

8217256128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77409 (or 77399 counting only the distinct ones).

The product of its digits is 107520, while the sum is 42.

The square root of 8217256128 is about 90649.0823340203. The cubic root of 8217256128 is about 2017.9432164107.

Subtracting from 8217256128 its reverse (8216527128), we obtain a cube (729000 = 90³).

The spelling of 8217256128 in words is "eight billion, two hundred seventeen million, two hundred fifty-six thousand, one hundred twenty-eight".