6640993 has 2 divisors, whose sum is σ = 6640994. Its totient is φ = 6640992.

The previous prime is 6640987. The next prime is 6641021. The reversal of 6640993 is 3990466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6640929 + 64 = 2577^2 + 8^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6640993 is a prime.

It is not a weakly prime, because it can be changed into another prime (6640903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3320496 + 3320497.

It is an arithmetic number, because the mean of its divisors is an integer number (3320497).

Almost surely, 2^6640993 is an apocalyptic number.

It is an amenable number.

6640993 is a deficient number, since it is larger than the sum of its proper divisors (1).

6640993 is an equidigital number, since it uses as much as digits as its factorization.

6640993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34992, while the sum is 37.

The square root of 6640993 is about 2577.0124175099. The cubic root of 6640993 is about 187.9652965218.

The spelling of 6640993 in words is "six million, six hundred forty thousand, nine hundred ninety-three".