2213721 has 12 divisors (see below), whose sum is σ = 3214848. Its totient is φ = 1467864.

The previous prime is 2213711. The next prime is 2213759. The reversal of 2213721 is 1273122.

2213721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 2213721 - 2⁷ = 2213593 is a prime.

It is a Smith number, since the sum of its digits (18) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2213694 and 2213703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2213711) 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 11 ways as a sum of consecutive naturals, for example, 1456 + ... + 2558.

It is an arithmetic number, because the mean of its divisors is an integer number (267904).

2^2213721 is an apocalyptic number.

It is an amenable number.

2213721 is a deficient number, since it is larger than the sum of its proper divisors (1001127).

2213721 is a wasteful number, since it uses less digits than its factorization.

2213721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1332 (or 1329 counting only the distinct ones).

The product of its digits is 168, while the sum is 18.

The square root of 2213721 is about 1487.8578561140. The cubic root of 2213721 is about 130.3289695900.

Adding to 2213721 its reverse (1273122), we get a palindrome (3486843).

The spelling of 2213721 in words is "two million, two hundred thirteen thousand, seven hundred twenty-one".