8991217 has 4 divisors (see below), whose sum is σ = 9138676. Its totient is φ = 8843760.

The previous prime is 8991197. The next prime is 8991223. The reversal of 8991217 is 7121998.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2835856 + 6155361 = 1684^2 + 2481^2 .

It is a cyclic number.

It is not a de Polignac number, because 8991217 - 2⁷ = 8991089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8991517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73638 + ... + 73759.

It is an arithmetic number, because the mean of its divisors is an integer number (2284669).

Almost surely, 2^8991217 is an apocalyptic number.

It is an amenable number.

8991217 is a deficient number, since it is larger than the sum of its proper divisors (147459).

8991217 is a wasteful number, since it uses less digits than its factorization.

8991217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147458.

The product of its digits is 9072, while the sum is 37.

The square root of 8991217 is about 2998.5358093576. The cubic root of 8991217 is about 207.9406959259.

It can be divided in two parts, 899 and 1217, that added together give a square (2116 = 46²).

The spelling of 8991217 in words is "eight million, nine hundred ninety-one thousand, two hundred seventeen".