7213221 has 6 divisors (see below), whose sum is σ = 10419110. Its totient is φ = 4808808.

The previous prime is 7213201. The next prime is 7213223. The reversal of 7213221 is 1223127.

It can be written as a sum of positive squares in only one way, i.e., 6320196 + 893025 = 2514^2 + 945^2 .

It is not a de Polignac number, because 7213221 - 2¹¹ = 7211173 is a prime.

It is a Duffinian number.

7213221 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 7213194 and 7213203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7213223) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 400726 + ... + 400743.

Almost surely, 2^7213221 is an apocalyptic number.

It is an amenable number.

7213221 is a deficient number, since it is larger than the sum of its proper divisors (3205889).

7213221 is a wasteful number, since it uses less digits than its factorization.

7213221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 801475 (or 801472 counting only the distinct ones).

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

The square root of 7213221 is about 2685.7440309903. The cubic root of 7213221 is about 193.2159966437.

Adding to 7213221 its reverse (1223127), we get a palindrome (8436348).

The spelling of 7213221 in words is "seven million, two hundred thirteen thousand, two hundred twenty-one".