8691221 has 16 divisors (see below), whose sum is σ = 11104128. Its totient is φ = 6604800.

The previous prime is 8691211. The next prime is 8691223. The reversal of 8691221 is 1221968.

It is a cyclic number.

It is not a de Polignac number, because 8691221 - 2⁶ = 8691157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8691223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1781 + ... + 4533.

It is an arithmetic number, because the mean of its divisors is an integer number (694008).

Almost surely, 2^8691221 is an apocalyptic number.

It is an amenable number.

8691221 is a deficient number, since it is larger than the sum of its proper divisors (2412907).

8691221 is a wasteful number, since it uses less digits than its factorization.

8691221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2812.

The product of its digits is 1728, while the sum is 29.

The square root of 8691221 is about 2948.0876852631. The cubic root of 8691221 is about 205.6018088053.

The spelling of 8691221 in words is "eight million, six hundred ninety-one thousand, two hundred twenty-one".