664066642 has 4 divisors (see below), whose sum is σ = 996099966. Its totient is φ = 332033320.

The previous prime is 664066591. The next prime is 664066661. The reversal of 664066642 is 246660466.

664066642 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 664041361 + 25281 = 25769^2 + 159^2 .

It is a junction number, because it is equal to n+sod(n) for n = 664066595 and 664066604.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166016659 + ... + 166016662.

Almost surely, 2^664066642 is an apocalyptic number.

664066642 is a deficient number, since it is larger than the sum of its proper divisors (332033324).

664066642 is a wasteful number, since it uses less digits than its factorization.

664066642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332033323.

The product of its (nonzero) digits is 248832, while the sum is 40.

The square root of 664066642 is about 25769.4905265898. The cubic root of 664066642 is about 872.4433197718.

The spelling of 664066642 in words is "six hundred sixty-four million, sixty-six thousand, six hundred forty-two".