2777221 has 4 divisors (see below), whose sum is σ = 2782444. Its totient is φ = 2772000.

The previous prime is 2777219. The next prime is 2777231. The reversal of 2777221 is 1227772.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1726596 + 1050625 = 1314^2 + 1025^2 .

It is a cyclic number.

It is not a de Polignac number, because 2777221 - 2¹ = 2777219 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2777221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2777231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1710 + ... + 2911.

It is an arithmetic number, because the mean of its divisors is an integer number (695611).

2^2777221 is an apocalyptic number.

It is an amenable number.

2777221 is a deficient number, since it is larger than the sum of its proper divisors (5223).

2777221 is an equidigital number, since it uses as much as digits as its factorization.

2777221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5222.

The product of its digits is 2744, while the sum is 28.

The square root of 2777221 is about 1666.4996249625. The cubic root of 2777221 is about 140.5627181647.

The spelling of 2777221 in words is "two million, seven hundred seventy-seven thousand, two hundred twenty-one".