6640289 has 2 divisors, whose sum is σ = 6640290. Its totient is φ = 6640288.

The previous prime is 6640241. The next prime is 6640297. The reversal of 6640289 is 9820466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4032064 + 2608225 = 2008^2 + 1615^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6640289 is a prime.

It is not a weakly prime, because it can be changed into another prime (6640589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3320144 + 3320145.

It is an arithmetic number, because the mean of its divisors is an integer number (3320145).

Almost surely, 2^6640289 is an apocalyptic number.

It is an amenable number.

6640289 is a deficient number, since it is larger than the sum of its proper divisors (1).

6640289 is an equidigital number, since it uses as much as digits as its factorization.

6640289 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 6640289 is about 2576.8758216103. The cubic root of 6640289 is about 187.9586543301.

The spelling of 6640289 in words is "six million, six hundred forty thousand, two hundred eighty-nine".