8421817 has 4 divisors (see below), whose sum is σ = 8917236. Its totient is φ = 7926400.

The previous prime is 8421799. The next prime is 8421821. The reversal of 8421817 is 7181248.

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 4016016 + 4405801 = 2004^2 + 2099^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8421817 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a d-powerful number, because it can be written as 8 + 4⁷ + 2²³ + 1 + 8 + 1 + 7⁵ .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8421827) 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, 247684 + ... + 247717.

It is an arithmetic number, because the mean of its divisors is an integer number (2229309).

Almost surely, 2^8421817 is an apocalyptic number.

It is an amenable number.

8421817 is a deficient number, since it is larger than the sum of its proper divisors (495419).

8421817 is a wasteful number, since it uses less digits than its factorization.

8421817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 495418.

The product of its digits is 3584, while the sum is 31.

The square root of 8421817 is about 2902.0366985963. The cubic root of 8421817 is about 203.4551090544.

The spelling of 8421817 in words is "eight million, four hundred twenty-one thousand, eight hundred seventeen".