8165221 has 2 divisors, whose sum is σ = 8165222. Its totient is φ = 8165220.

The previous prime is 8165149. The next prime is 8165239. The reversal of 8165221 is 1225618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7214596 + 950625 = 2686^2 + 975^2 .

It is a cyclic number.

It is not a de Polignac number, because 8165221 - 2⁷ = 8165093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8105221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4082610 + 4082611.

It is an arithmetic number, because the mean of its divisors is an integer number (4082611).

Almost surely, 2^8165221 is an apocalyptic number.

It is an amenable number.

8165221 is a deficient number, since it is larger than the sum of its proper divisors (1).

8165221 is an equidigital number, since it uses as much as digits as its factorization.

8165221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 960, while the sum is 25.

The square root of 8165221 is about 2857.4850830757. The cubic root of 8165221 is about 201.3674704796.

The spelling of 8165221 in words is "eight million, one hundred sixty-five thousand, two hundred twenty-one".