8228156221 has 2 divisors, whose sum is σ = 8228156222. Its totient is φ = 8228156220.

The previous prime is 8228156219. The next prime is 8228156257. The reversal of 8228156221 is 1226518228.

8228156221 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7244392996 + 983763225 = 85114^2 + 31365^2 .

It is a cyclic number.

It is not a de Polignac number, because 8228156221 - 2¹ = 8228156219 is a prime.

Together with 8228156219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8228256221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4114078110 + 4114078111.

It is an arithmetic number, because the mean of its divisors is an integer number (4114078111).

Almost surely, 2^8228156221 is an apocalyptic number.

It is an amenable number.

8228156221 is a deficient number, since it is larger than the sum of its proper divisors (1).

8228156221 is an equidigital number, since it uses as much as digits as its factorization.

8228156221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30720, while the sum is 37.

The square root of 8228156221 is about 90709.1848767257. The cubic root of 8228156221 is about 2018.8350814420.

The spelling of 8228156221 in words is "eight billion, two hundred twenty-eight million, one hundred fifty-six thousand, two hundred twenty-one".