999999197 has 2 divisors, whose sum is σ = 999999198. Its totient is φ = 999999196.

The previous prime is 999999193. The next prime is 999999223. The reversal of 999999197 is 791999999.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 999887641 + 111556 = 31621^2 + 334^2 .

It is a cyclic number.

It is not a de Polignac number, because 999999197 - 2² = 999999193 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 999999197.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999999191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499999598 + 499999599.

It is an arithmetic number, because the mean of its divisors is an integer number (499999599).

Almost surely, 2^999999197 is an apocalyptic number.

It is an amenable number.

999999197 is a deficient number, since it is larger than the sum of its proper divisors (1).

999999197 is an equidigital number, since it uses as much as digits as its factorization.

999999197 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 33480783, while the sum is 71.

The square root of 999999197 is about 31622.7639051364. The cubic root of 999999197 is about 999.9997323333. Note that the first 3 decimals are identical.

The spelling of 999999197 in words is "nine hundred ninety-nine million, nine hundred ninety-nine thousand, one hundred ninety-seven".