6815221 has 8 divisors (see below), whose sum is σ = 7824960. Its totient is φ = 5814528.

The previous prime is 6815161. The next prime is 6815227. The reversal of 6815221 is 1225186.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6815221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6815227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 556 + ... + 3733.

It is an arithmetic number, because the mean of its divisors is an integer number (978120).

Almost surely, 2^6815221 is an apocalyptic number.

It is an amenable number.

6815221 is a deficient number, since it is larger than the sum of its proper divisors (1009739).

6815221 is a wasteful number, since it uses less digits than its factorization.

6815221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4523.

The product of its digits is 960, while the sum is 25.

The square root of 6815221 is about 2610.5978242541. The cubic root of 6815221 is about 189.5948986652.

The spelling of 6815221 in words is "six million, eight hundred fifteen thousand, two hundred twenty-one".