1997909934217 has 2 divisors, whose sum is σ = 1997909934218. Its totient is φ = 1997909934216.

The previous prime is 1997909934211. The next prime is 1997909934233. The reversal of 1997909934217 is 7124399097991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1221579773001 + 776330161216 = 1105251^2 + 881096^2 .

It is a cyclic number.

It is not a de Polignac number, because 1997909934217 - 2²³ = 1997901545609 is a prime.

It is not a weakly prime, because it can be changed into another prime (1997909934211) 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, 998954967108 + 998954967109.

It is an arithmetic number, because the mean of its divisors is an integer number (998954967109).

Almost surely, 2^{1997909934217} is an apocalyptic number.

It is an amenable number.

1997909934217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1997909934217 is an equidigital number, since it uses as much as digits as its factorization.

1997909934217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69441624, while the sum is 70.

The spelling of 1997909934217 in words is "one trillion, nine hundred ninety-seven billion, nine hundred nine million, nine hundred thirty-four thousand, two hundred seventeen".