1998665370181 has 2 divisors, whose sum is σ = 1998665370182. Its totient is φ = 1998665370180.

The previous prime is 1998665370089. The next prime is 1998665370259. The reversal of 1998665370181 is 1810735668991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1726948169956 + 271717200225 = 1314134^2 + 521265^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1998665370181 is a prime.

It is a super-2 number, since 2×1998665370181² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1998665320181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999332685090 + 999332685091.

It is an arithmetic number, because the mean of its divisors is an integer number (999332685091).

Almost surely, 2^{1998665370181} is an apocalyptic number.

It is an amenable number.

1998665370181 is a deficient number, since it is larger than the sum of its proper divisors (1).

1998665370181 is an equidigital number, since it uses as much as digits as its factorization.

1998665370181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19595520, while the sum is 64.

The spelling of 1998665370181 in words is "one trillion, nine hundred ninety-eight billion, six hundred sixty-five million, three hundred seventy thousand, one hundred eighty-one".