8618221 has 2 divisors, whose sum is σ = 8618222. Its totient is φ = 8618220.

The previous prime is 8618213. The next prime is 8618237. The reversal of 8618221 is 1228168.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7590025 + 1028196 = 2755^2 + 1014^2 .

It is a cyclic number.

It is not a de Polignac number, because 8618221 - 2³ = 8618213 is a prime.

It is a Chen prime.

8618221 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 8618221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8618251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4309110 + 4309111.

It is an arithmetic number, because the mean of its divisors is an integer number (4309111).

Almost surely, 2^8618221 is an apocalyptic number.

It is an amenable number.

8618221 is a deficient number, since it is larger than the sum of its proper divisors (1).

8618221 is an equidigital number, since it uses as much as digits as its factorization.

8618221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1536, while the sum is 28.

The square root of 8618221 is about 2935.6806706452. The cubic root of 8618221 is about 205.0245538704.

The spelling of 8618221 in words is "eight million, six hundred eighteen thousand, two hundred twenty-one".