664643326 has 4 divisors (see below), whose sum is σ = 996964992. Its totient is φ = 332321662.

The previous prime is 664643311. The next prime is 664643363. The reversal of 664643326 is 623346466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 623346466 = 2 ⋅311673233.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166160830 + ... + 166160833.

It is an arithmetic number, because the mean of its divisors is an integer number (249241248).

Almost surely, 2^664643326 is an apocalyptic number.

664643326 is a deficient number, since it is larger than the sum of its proper divisors (332321666).

664643326 is a wasteful number, since it uses less digits than its factorization.

664643326 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332321665.

The product of its digits is 373248, while the sum is 40.

The square root of 664643326 is about 25780.6773766711. The cubic root of 664643326 is about 872.6957936964.

The spelling of 664643326 in words is "six hundred sixty-four million, six hundred forty-three thousand, three hundred twenty-six".