8406221 has 2 divisors, whose sum is σ = 8406222. Its totient is φ = 8406220.

The previous prime is 8406193. The next prime is 8406253. The reversal of 8406221 is 1226048.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8185321 + 220900 = 2861^2 + 470^2 .

It is a cyclic number.

It is not a de Polignac number, because 8406221 - 2¹⁰ = 8405197 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8402221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4203110 + 4203111.

It is an arithmetic number, because the mean of its divisors is an integer number (4203111).

Almost surely, 2^8406221 is an apocalyptic number.

It is an amenable number.

8406221 is a deficient number, since it is larger than the sum of its proper divisors (1).

8406221 is an equidigital number, since it uses as much as digits as its factorization.

8406221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 8406221 is about 2899.3483750664. The cubic root of 8406221 is about 203.3294415332.

The spelling of 8406221 in words is "eight million, four hundred six thousand, two hundred twenty-one".