664654666 has 8 divisors (see below), whose sum is σ = 1073672964. Its totient is φ = 306763680.

The previous prime is 664654657. The next prime is 664654691. The reversal of 664654666 is 666456466.

It can be written as a sum of positive squares in 2 ways, for example, as 661981441 + 2673225 = 25729^2 + 1635^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12781795 + ... + 12781846.

Almost surely, 2^664654666 is an apocalyptic number.

664654666 is a deficient number, since it is larger than the sum of its proper divisors (409018298).

664654666 is a wasteful number, since it uses less digits than its factorization.

664654666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25563656.

The product of its digits is 3732480, while the sum is 49.

The square root of 664654666 is about 25780.8973078906. The cubic root of 664654666 is about 872.7007569168.

The spelling of 664654666 in words is "six hundred sixty-four million, six hundred fifty-four thousand, six hundred sixty-six".