4391221 has 2 divisors, whose sum is σ = 4391222. Its totient is φ = 4391220.

The previous prime is 4391161. The next prime is 4391227. The reversal of 4391221 is 1221934.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2856100 + 1535121 = 1690^2 + 1239^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4391221 is a prime.

It is a nialpdrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 4391192 and 4391201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4391227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2195610 + 2195611.

It is an arithmetic number, because the mean of its divisors is an integer number (2195611).

Almost surely, 2^4391221 is an apocalyptic number.

It is an amenable number.

4391221 is a deficient number, since it is larger than the sum of its proper divisors (1).

4391221 is an equidigital number, since it uses as much as digits as its factorization.

4391221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 22.

The square root of 4391221 is about 2095.5240394708. The cubic root of 4391221 is about 163.7551994153.

The spelling of 4391221 in words is "four million, three hundred ninety-one thousand, two hundred twenty-one".