6640091 has 2 divisors, whose sum is σ = 6640092. Its totient is φ = 6640090.

The previous prime is 6640079. The next prime is 6640093. The reversal of 6640091 is 1900466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6640091 - 2⁶ = 6640027 is a prime.

Together with 6640093, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6640091.

It is not a weakly prime, because it can be changed into another prime (6640093) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3320045 + 3320046.

It is an arithmetic number, because the mean of its divisors is an integer number (3320046).

Almost surely, 2^6640091 is an apocalyptic number.

6640091 is a deficient number, since it is larger than the sum of its proper divisors (1).

6640091 is an equidigital number, since it uses as much as digits as its factorization.

6640091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 6640091 is about 2576.8374027090. The cubic root of 6640091 is about 187.9567861291.

The spelling of 6640091 in words is "six million, six hundred forty thousand, ninety-one".