97991220211021 has 2 divisors, whose sum is σ = 97991220211022. Its totient is φ = 97991220211020.

The previous prime is 97991220210959. The next prime is 97991220211033. The reversal of 97991220211021 is 12011202219979.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50082867455625 + 47908352755396 = 7076925^2 + 6921586^2 .

It is an emirp because it is prime and its reverse (12011202219979) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 97991220211021 - 2³¹ = 97989072727373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (97991220211421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 48995610105510 + 48995610105511.

It is an arithmetic number, because the mean of its divisors is an integer number (48995610105511).

Almost surely, 2^{97991220211021} is an apocalyptic number.

It is an amenable number.

97991220211021 is a deficient number, since it is larger than the sum of its proper divisors (1).

97991220211021 is an equidigital number, since it uses as much as digits as its factorization.

97991220211021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81648, while the sum is 46.

The spelling of 97991220211021 in words is "ninety-seven trillion, nine hundred ninety-one billion, two hundred twenty million, two hundred eleven thousand, twenty-one".