6640939 has 2 divisors, whose sum is σ = 6640940. Its totient is φ = 6640938.

The previous prime is 6640927. The next prime is 6640967. The reversal of 6640939 is 9390466.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6640939 is a prime.

It is a Chen prime.

6640939 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 6640898 and 6640907.

It is not a weakly prime, because it can be changed into another prime (6640979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3320469 + 3320470.

It is an arithmetic number, because the mean of its divisors is an integer number (3320470).

Almost surely, 2^6640939 is an apocalyptic number.

6640939 is a deficient number, since it is larger than the sum of its proper divisors (1).

6640939 is an equidigital number, since it uses as much as digits as its factorization.

6640939 is an evil number, because the sum of its binary digits is even.

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

The square root of 6640939 is about 2577.0019402399. The cubic root of 6640939 is about 187.9647870521.

The spelling of 6640939 in words is "six million, six hundred forty thousand, nine hundred thirty-nine".