8216491 has 4 divisors (see below), whose sum is σ = 8699832. Its totient is φ = 7733152.

The previous prime is 8216489. The next prime is 8216503. The reversal of 8216491 is 1946128.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 8216491 - 2¹ = 8216489 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 an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8216471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 241645 + ... + 241678.

It is an arithmetic number, because the mean of its divisors is an integer number (2174958).

Almost surely, 2^8216491 is an apocalyptic number.

8216491 is a deficient number, since it is larger than the sum of its proper divisors (483341).

8216491 is a wasteful number, since it uses less digits than its factorization.

8216491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 483340.

The product of its digits is 3456, while the sum is 31.

The square root of 8216491 is about 2866.4422198956. The cubic root of 8216491 is about 201.7880582657.

The spelling of 8216491 in words is "eight million, two hundred sixteen thousand, four hundred ninety-one".