8403221 has 2 divisors, whose sum is σ = 8403222. Its totient is φ = 8403220.

The previous prime is 8403217. The next prime is 8403223. The reversal of 8403221 is 1223048.

8403221 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5340721 + 3062500 = 2311^2 + 1750^2 .

It is a cyclic number.

It is not a de Polignac number, because 8403221 - 2² = 8403217 is a prime.

It is a super-2 number, since 2×8403221² = 141228246349682, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 8403223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 8403193 and 8403202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8403223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4201610 + 4201611.

It is an arithmetic number, because the mean of its divisors is an integer number (4201611).

Almost surely, 2^8403221 is an apocalyptic number.

It is an amenable number.

8403221 is a deficient number, since it is larger than the sum of its proper divisors (1).

8403221 is an equidigital number, since it uses as much as digits as its factorization.

8403221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 8403221 is about 2898.8309712710. The cubic root of 8403221 is about 203.3052506828.

Adding to 8403221 its reverse (1223048), we get a palindrome (9626269).

The spelling of 8403221 in words is "eight million, four hundred three thousand, two hundred twenty-one".