2787221 has 8 divisors (see below), whose sum is σ = 2880024. Its totient is φ = 2695680.

The previous prime is 2787181. The next prime is 2787227. The reversal of 2787221 is 1227872.

2787221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 130321 + 2656900 = 361^2 + 1630^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 2787221 - 2⁶ = 2787157 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 (2787227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6221 + ... + 6653.

It is an arithmetic number, because the mean of its divisors is an integer number (360003).

2^2787221 is an apocalyptic number.

It is an amenable number.

2787221 is a deficient number, since it is larger than the sum of its proper divisors (92803).

2787221 is a wasteful number, since it uses less digits than its factorization.

2787221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 631.

The product of its digits is 3136, while the sum is 29.

The square root of 2787221 is about 1669.4972297072. The cubic root of 2787221 is about 140.7312251552.

The spelling of 2787221 in words is "two million, seven hundred eighty-seven thousand, two hundred twenty-one".