8563921 has 4 divisors (see below), whose sum is σ = 8570212. Its totient is φ = 8557632.

The previous prime is 8563901. The next prime is 8563939. The reversal of 8563921 is 1293658.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 5452225 + 3111696 = 2335^2 + 1764^2 .

It is a cyclic number.

It is not a de Polignac number, because 8563921 - 2¹⁵ = 8531153 is a prime.

It is a Duffinian number.

8563921 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (8563901) 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, 156 + ... + 4141.

It is an arithmetic number, because the mean of its divisors is an integer number (2142553).

Almost surely, 2^8563921 is an apocalyptic number.

It is an amenable number.

8563921 is a deficient number, since it is larger than the sum of its proper divisors (6291).

8563921 is a wasteful number, since it uses less digits than its factorization.

8563921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6290.

The product of its digits is 12960, while the sum is 34.

The square root of 8563921 is about 2926.4177760532. The cubic root of 8563921 is about 204.5930535002.

The spelling of 8563921 in words is "eight million, five hundred sixty-three thousand, nine hundred twenty-one".