8921221 has 4 divisors (see below), whose sum is σ = 9046944. Its totient is φ = 8795500.

The previous prime is 8921207. The next prime is 8921239. The reversal of 8921221 is 1221298.

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 8921221 - 2¹¹ = 8919173 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 (8921261) 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, 62755 + ... + 62896.

It is an arithmetic number, because the mean of its divisors is an integer number (2261736).

Almost surely, 2^8921221 is an apocalyptic number.

It is an amenable number.

8921221 is a deficient number, since it is larger than the sum of its proper divisors (125723).

8921221 is a wasteful number, since it uses less digits than its factorization.

8921221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125722.

The product of its digits is 576, while the sum is 25.

The square root of 8921221 is about 2986.8413081381. The cubic root of 8921221 is about 207.3996882926.

The spelling of 8921221 in words is "eight million, nine hundred twenty-one thousand, two hundred twenty-one".