4991009 has 2 divisors, whose sum is σ = 4991010. Its totient is φ = 4991008.

The previous prime is 4990981. The next prime is 4991011. The reversal of 4991009 is 9001994.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3598609 + 1392400 = 1897^2 + 1180^2 .

It is a cyclic number.

It is not a de Polignac number, because 4991009 - 2⁸ = 4990753 is a prime.

Together with 4991011, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (4991029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2495504 + 2495505.

It is an arithmetic number, because the mean of its divisors is an integer number (2495505).

Almost surely, 2^4991009 is an apocalyptic number.

It is an amenable number.

4991009 is a deficient number, since it is larger than the sum of its proper divisors (1).

4991009 is an equidigital number, since it uses as much as digits as its factorization.

4991009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 4991009 is about 2234.0566241705. The cubic root of 4991009 is about 170.8950372119.

The spelling of 4991009 in words is "four million, nine hundred ninety-one thousand, nine".