8220521971 has 2 divisors, whose sum is σ = 8220521972. Its totient is φ = 8220521970.

The previous prime is 8220521963. The next prime is 8220522049. The reversal of 8220521971 is 1791250228.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 8220521971 - 2³ = 8220521963 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 8220521971.

It is not a weakly prime, because it can be changed into another prime (8220521671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4110260985 + 4110260986.

It is an arithmetic number, because the mean of its divisors is an integer number (4110260986).

Almost surely, 2^8220521971 is an apocalyptic number.

8220521971 is a deficient number, since it is larger than the sum of its proper divisors (1).

8220521971 is an equidigital number, since it uses as much as digits as its factorization.

8220521971 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20160, while the sum is 37.

The square root of 8220521971 is about 90667.0942018106. The cubic root of 8220521971 is about 2018.2105162143.

The spelling of 8220521971 in words is "eight billion, two hundred twenty million, five hundred twenty-one thousand, nine hundred seventy-one".