6643489 has 2 divisors, whose sum is σ = 6643490. Its totient is φ = 6643488.

The previous prime is 6643487. The next prime is 6643499. The reversal of 6643489 is 9843466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6477025 + 166464 = 2545^2 + 408^2 .

It is a cyclic number.

It is not a de Polignac number, because 6643489 - 2¹ = 6643487 is a prime.

Together with 6643487, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (6643487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3321744 + 3321745.

It is an arithmetic number, because the mean of its divisors is an integer number (3321745).

Almost surely, 2^6643489 is an apocalyptic number.

It is an amenable number.

6643489 is a deficient number, since it is larger than the sum of its proper divisors (1).

6643489 is an equidigital number, since it uses as much as digits as its factorization.

6643489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 124416, while the sum is 40.

The square root of 6643489 is about 2577.4966537321. The cubic root of 6643489 is about 187.9888423286.

The spelling of 6643489 in words is "six million, six hundred forty-three thousand, four hundred eighty-nine".