8221209989 has 2 divisors, whose sum is σ = 8221209990. Its totient is φ = 8221209988.

The previous prime is 8221209943. The next prime is 8221210001. The reversal of 8221209989 is 9899021228.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4895381089 + 3325828900 = 69967^2 + 57670^2 .

It is a cyclic number.

It is not a de Polignac number, because 8221209989 - 2¹⁶ = 8221144453 is a prime.

It is a Sophie Germain 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 (8221209929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4110604994 + 4110604995.

It is an arithmetic number, because the mean of its divisors is an integer number (4110604995).

Almost surely, 2^8221209989 is an apocalyptic number.

It is an amenable number.

8221209989 is a deficient number, since it is larger than the sum of its proper divisors (1).

8221209989 is an equidigital number, since it uses as much as digits as its factorization.

8221209989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 373248, while the sum is 50.

The square root of 8221209989 is about 90670.8883214453. Note that the first 3 decimals coincide. The cubic root of 8221209989 is about 2018.2668194689.

The spelling of 8221209989 in words is "eight billion, two hundred twenty-one million, two hundred nine thousand, nine hundred eighty-nine".