999991207 has 2 divisors, whose sum is σ = 999991208. Its totient is φ = 999991206.

The previous prime is 999991163. The next prime is 999991229. The reversal of 999991207 is 702199999.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-999991207 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999991277) 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, 499995603 + 499995604.

It is an arithmetic number, because the mean of its divisors is an integer number (499995604).

Almost surely, 2^999991207 is an apocalyptic number.

999991207 is a deficient number, since it is larger than the sum of its proper divisors (1).

999991207 is an equidigital number, since it uses as much as digits as its factorization.

999991207 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 826686, while the sum is 55.

The square root of 999991207 is about 31622.6375718408. The cubic root of 999991207 is about 999.9970689914.

The spelling of 999991207 in words is "nine hundred ninety-nine million, nine hundred ninety-one thousand, two hundred seven".