664651066 has 4 divisors (see below), whose sum is σ = 996976602. Its totient is φ = 332325532.

The previous prime is 664651061. The next prime is 664651073. The reversal of 664651066 is 660156466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 660156466 = 2 ⋅330078233.

It can be written as a sum of positive squares in only one way, i.e., 397165041 + 267486025 = 19929^2 + 16355^2 .

It is a super-2 number, since 2×664651066² = 883522079069872712, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (664651061) by changing a digit.

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 as a sum of consecutive naturals, namely, 166162765 + ... + 166162768.

Almost surely, 2^664651066 is an apocalyptic number.

664651066 is a deficient number, since it is larger than the sum of its proper divisors (332325536).

664651066 is a wasteful number, since it uses less digits than its factorization.

664651066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332325535.

The product of its (nonzero) digits is 155520, while the sum is 40.

The square root of 664651066 is about 25780.8274886591. The cubic root of 664651066 is about 872.6991812974.

The spelling of 664651066 in words is "six hundred sixty-four million, six hundred fifty-one thousand, sixty-six".