197992198021 has 2 divisors, whose sum is σ = 197992198022. Its totient is φ = 197992198020.

The previous prime is 197992198013. The next prime is 197992198039. The reversal of 197992198021 is 120891299791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 178961995521 + 19030202500 = 423039^2 + 137950^2 .

It is a cyclic number.

It is not a de Polignac number, because 197992198021 - 2³ = 197992198013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (197992118021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 98996099010 + 98996099011.

It is an arithmetic number, because the mean of its divisors is an integer number (98996099011).

Almost surely, 2^197992198021 is an apocalyptic number.

It is an amenable number.

197992198021 is a deficient number, since it is larger than the sum of its proper divisors (1).

197992198021 is an equidigital number, since it uses as much as digits as its factorization.

197992198021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1469664, while the sum is 58.

The spelling of 197992198021 in words is "one hundred ninety-seven billion, nine hundred ninety-two million, one hundred ninety-eight thousand, twenty-one".