8539221997 has 2 divisors, whose sum is σ = 8539221998. Its totient is φ = 8539221996.

The previous prime is 8539221967. The next prime is 8539222033. The reversal of 8539221997 is 7991229358.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7847479396 + 691742601 = 88586^2 + 26301^2 .

It is a cyclic number.

It is not a de Polignac number, because 8539221997 - 2⁷ = 8539221869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8539221917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4269610998 + 4269610999.

It is an arithmetic number, because the mean of its divisors is an integer number (4269610999).

Almost surely, 2^8539221997 is an apocalyptic number.

It is an amenable number.

8539221997 is a deficient number, since it is larger than the sum of its proper divisors (1).

8539221997 is an equidigital number, since it uses as much as digits as its factorization.

8539221997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2449440, while the sum is 55.

The square root of 8539221997 is about 92407.9109005284. The cubic root of 8539221997 is about 2043.9617677275.

The spelling of 8539221997 in words is "eight billion, five hundred thirty-nine million, two hundred twenty-one thousand, nine hundred ninety-seven".