7865221 has 16 divisors (see below), whose sum is σ = 10192000. Its totient is φ = 5894208.

The previous prime is 7865171. The next prime is 7865257. The reversal of 7865221 is 1225687.

It is a cyclic number.

It is not a de Polignac number, because 7865221 - 2²¹ = 5768069 is a prime.

It is a d-powerful number, because it can be written as 7⁸ + 8 + 6 + 5⁵ + 2⁷ + 2²¹ + 1 .

It is the 2805-th Hogben number.

7865221 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7865261) by changing a digit.

It is a nontrivial repunit in base 2804.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 546 + ... + 4003.

It is an arithmetic number, because the mean of its divisors is an integer number (637000).

Almost surely, 2^7865221 is an apocalyptic number.

It is an amenable number.

7865221 is a deficient number, since it is larger than the sum of its proper divisors (2326779).

7865221 is a wasteful number, since it uses less digits than its factorization.

7865221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4588.

The product of its digits is 6720, while the sum is 31.

The square root of 7865221 is about 2804.5001337137. The cubic root of 7865221 is about 198.8704745368.

The spelling of 7865221 in words is "seven million, eight hundred sixty-five thousand, two hundred twenty-one".