8538221 has 4 divisors (see below), whose sum is σ = 8909472. Its totient is φ = 8166972.

The previous prime is 8538193. The next prime is 8538223. The reversal of 8538221 is 1228358.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1228358 = 2 ⋅614179.

It is a cyclic number.

It is not a de Polignac number, because 8538221 - 2¹⁰ = 8537197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8538223) 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, 185591 + ... + 185636.

It is an arithmetic number, because the mean of its divisors is an integer number (2227368).

Almost surely, 2^8538221 is an apocalyptic number.

It is an amenable number.

8538221 is a deficient number, since it is larger than the sum of its proper divisors (371251).

8538221 is a wasteful number, since it uses less digits than its factorization.

8538221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 371250.

The product of its digits is 3840, while the sum is 29.

The square root of 8538221 is about 2922.0234427533. The cubic root of 8538221 is about 204.3881897862.

The spelling of 8538221 in words is "eight million, five hundred thirty-eight thousand, two hundred twenty-one".