999912197 has 2 divisors, whose sum is σ = 999912198. Its totient is φ = 999912196.

The previous prime is 999912167. The next prime is 999912203. The reversal of 999912197 is 791219999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 820593316 + 179318881 = 28646^2 + 13391^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-999912197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999912167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499956098 + 499956099.

It is an arithmetic number, because the mean of its divisors is an integer number (499956099).

Almost surely, 2^999912197 is an apocalyptic number.

It is an amenable number.

999912197 is a deficient number, since it is larger than the sum of its proper divisors (1).

999912197 is an equidigital number, since it uses as much as digits as its factorization.

999912197 is an evil number, because the sum of its binary digits is even.

The product of its digits is 826686, while the sum is 56.

The square root of 999912197 is about 31621.3882838815. The cubic root of 999912197 is about 999.9707314767.

The spelling of 999912197 in words is "nine hundred ninety-nine million, nine hundred twelve thousand, one hundred ninety-seven".