6664661 has 2 divisors, whose sum is σ = 6664662. Its totient is φ = 6664660.

The previous prime is 6664657. The next prime is 6664667. The reversal of 6664661 is 1664666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4024036 + 2640625 = 2006^2 + 1625^2 .

It is a cyclic number.

It is not a de Polignac number, because 6664661 - 2² = 6664657 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6664667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3332330 + 3332331.

It is an arithmetic number, because the mean of its divisors is an integer number (3332331).

Almost surely, 2^6664661 is an apocalyptic number.

It is an amenable number.

6664661 is a deficient number, since it is larger than the sum of its proper divisors (1).

6664661 is an equidigital number, since it uses as much as digits as its factorization.

6664661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 35.

The square root of 6664661 is about 2581.6004725751. The cubic root of 6664661 is about 188.1883298372.

The spelling of 6664661 in words is "six million, six hundred sixty-four thousand, six hundred sixty-one".