2660221 has 4 divisors (see below), whose sum is σ = 2675772. Its totient is φ = 2644672.

The previous prime is 2660219. The next prime is 2660237. The reversal of 2660221 is 1220662.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1220662 = 2 ⋅610331.

It can be written as a sum of positive squares in 2 ways, for example, as 2592100 + 68121 = 1610^2 + 261^2 .

It is a cyclic number.

It is not a de Polignac number, because 2660221 - 2¹ = 2660219 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 (2660291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7516 + ... + 7861.

It is an arithmetic number, because the mean of its divisors is an integer number (668943).

2^2660221 is an apocalyptic number.

It is an amenable number.

2660221 is a deficient number, since it is larger than the sum of its proper divisors (15551).

2660221 is a wasteful number, since it uses less digits than its factorization.

2660221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15550.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 2660221 is about 1631.0183935198. The cubic root of 2660221 is about 138.5604353364.

Adding to 2660221 its reverse (1220662), we get a palindrome (3880883).

The spelling of 2660221 in words is "two million, six hundred sixty thousand, two hundred twenty-one".