20212121197 has 2 divisors, whose sum is σ = 20212121198. Its totient is φ = 20212121196.

The previous prime is 20212121191. The next prime is 20212121201. The reversal of 20212121197 is 79112121202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17117535556 + 3094585641 = 130834^2 + 55629^2 .

It is a cyclic number.

It is not a de Polignac number, because 20212121197 - 2¹¹ = 20212119149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20212121191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10106060598 + 10106060599.

It is an arithmetic number, because the mean of its divisors is an integer number (10106060599).

Almost surely, 2^20212121197 is an apocalyptic number.

It is an amenable number.

20212121197 is a deficient number, since it is larger than the sum of its proper divisors (1).

20212121197 is an equidigital number, since it uses as much as digits as its factorization.

20212121197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 28.

Adding to 20212121197 its reverse (79112121202), we get a palindrome (99324242399).

The spelling of 20212121197 in words is "twenty billion, two hundred twelve million, one hundred twenty-one thousand, one hundred ninety-seven".