999244991 has 2 divisors, whose sum is σ = 999244992. Its totient is φ = 999244990.

The previous prime is 999244969. The next prime is 999244997. The reversal of 999244991 is 199442999.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 999244991 - 2⁶ = 999244927 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999244997) 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, 499622495 + 499622496.

It is an arithmetic number, because the mean of its divisors is an integer number (499622496).

Almost surely, 2^999244991 is an apocalyptic number.

999244991 is a deficient number, since it is larger than the sum of its proper divisors (1).

999244991 is an equidigital number, since it uses as much as digits as its factorization.

999244991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1889568, while the sum is 56.

The square root of 999244991 is about 31610.8366070878. The cubic root of 999244991 is about 999.7482669691.

The spelling of 999244991 in words is "nine hundred ninety-nine million, two hundred forty-four thousand, nine hundred ninety-one".