2223721 has 4 divisors (see below), whose sum is σ = 2265732. Its totient is φ = 2181712.

The previous prime is 2223713. The next prime is 2223731. The reversal of 2223721 is 1273222.

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 1413721 + 810000 = 1189^2 + 900^2 .

It is a cyclic number.

It is not a de Polignac number, because 2223721 - 2³ = 2223713 is a prime.

It is a Duffinian number.

2223721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2223701) 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, 20926 + ... + 21031.

It is an arithmetic number, because the mean of its divisors is an integer number (566433).

2^2223721 is an apocalyptic number.

It is an amenable number.

2223721 is a deficient number, since it is larger than the sum of its proper divisors (42011).

2223721 is an equidigital number, since it uses as much as digits as its factorization.

2223721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42010.

The product of its digits is 336, while the sum is 19.

The square root of 2223721 is about 1491.2146056152. The cubic root of 2223721 is about 130.5249190290.

Adding to 2223721 its reverse (1273222), we get a palindrome (3496943).

The spelling of 2223721 in words is "two million, two hundred twenty-three thousand, seven hundred twenty-one".