6649661 has 2 divisors, whose sum is σ = 6649662. Its totient is φ = 6649660.

The previous prime is 6649633. The next prime is 6649681. The reversal of 6649661 is 1669466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4813636 + 1836025 = 2194^2 + 1355^2 .

It is a cyclic number.

It is not a de Polignac number, because 6649661 - 2¹⁰ = 6648637 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6649631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3324830 + 3324831.

It is an arithmetic number, because the mean of its divisors is an integer number (3324831).

Almost surely, 2^6649661 is an apocalyptic number.

It is an amenable number.

6649661 is a deficient number, since it is larger than the sum of its proper divisors (1).

6649661 is an equidigital number, since it uses as much as digits as its factorization.

6649661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46656, while the sum is 38.

The square root of 6649661 is about 2578.6936615271. The cubic root of 6649661 is about 188.0470400624.

The spelling of 6649661 in words is "six million, six hundred forty-nine thousand, six hundred sixty-one".