6663749 has 2 divisors, whose sum is σ = 6663750. Its totient is φ = 6663748.

The previous prime is 6663739. The next prime is 6663751. The reversal of 6663749 is 9473666.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6630625 + 33124 = 2575^2 + 182^2 .

It is a cyclic number.

It is not a de Polignac number, because 6663749 - 2⁸ = 6663493 is a prime.

It is a Sophie Germain prime.

Together with 6663751, it forms a pair of twin primes.

It is a Chen prime.

It is a d-powerful number, because it can be written as 6⁷ + 6⁷ + 6⁷ + 3³ + 7⁸ + 4³ + 9⁵ .

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6663739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3331874 + 3331875.

It is an arithmetic number, because the mean of its divisors is an integer number (3331875).

Almost surely, 2^6663749 is an apocalyptic number.

It is an amenable number.

6663749 is a deficient number, since it is larger than the sum of its proper divisors (1).

6663749 is an equidigital number, since it uses as much as digits as its factorization.

6663749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 163296, while the sum is 41.

The square root of 6663749 is about 2581.4238319191. The cubic root of 6663749 is about 188.1797454753.

The spelling of 6663749 in words is "six million, six hundred sixty-three thousand, seven hundred forty-nine".