7312221 has 24 divisors (see below), whose sum is σ = 12603840. Its totient is φ = 4177656.

The previous prime is 7312177. The next prime is 7312231. The reversal of 7312221 is 1222137.

It is not a de Polignac number, because 7312221 - 2⁶ = 7312157 is a prime.

It is a Curzon number.

7312221 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 7312194 and 7312203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7312231) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1441 + ... + 4086.

It is an arithmetic number, because the mean of its divisors is an integer number (525160).

Almost surely, 2^7312221 is an apocalyptic number.

It is an amenable number.

7312221 is a deficient number, since it is larger than the sum of its proper divisors (5291619).

7312221 is a wasteful number, since it uses less digits than its factorization.

7312221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5550 (or 5537 counting only the distinct ones).

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

The square root of 7312221 is about 2704.1118689877. Note that the first 3 decimals coincide. The cubic root of 7312221 is about 194.0959333515.

Adding to 7312221 its reverse (1222137), we get a palindrome (8534358).

The spelling of 7312221 in words is "seven million, three hundred twelve thousand, two hundred twenty-one".