8221815 has 48 divisors (see below), whose sum is σ = 16693248. Its totient is φ = 3665088.

The previous prime is 8221793. The next prime is 8221823. The reversal of 8221815 is 5181228.

8221815 = T₁₆₂ + T₁₆₃ + ... + T₃₇₆.

It is not a de Polignac number, because 8221815 - 2⁶ = 8221751 is a prime.

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 13242 + ... + 13848.

It is an arithmetic number, because the mean of its divisors is an integer number (347776).

Almost surely, 2^8221815 is an apocalyptic number.

8221815 is an abundant number, since it is smaller than the sum of its proper divisors (8471433).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

8221815 is a wasteful number, since it uses less digits than its factorization.

8221815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 668 (or 665 counting only the distinct ones).

The product of its digits is 1280, while the sum is 27.

The square root of 8221815 is about 2867.3707468690. The cubic root of 8221815 is about 201.8316327334.

The spelling of 8221815 in words is "eight million, two hundred twenty-one thousand, eight hundred fifteen".