664999968 has 24 divisors (see below), whose sum is σ = 1745625168. Its totient is φ = 221666624.

The previous prime is 664999949. The next prime is 665000027. The reversal of 664999968 is 869999466.

It is a tau number, because it is divible by the number of its divisors (24).

It is a junction number, because it is equal to n+sod(n) for n = 664999899 and 664999908.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3463446 + ... + 3463637.

It is an arithmetic number, because the mean of its divisors is an integer number (72734382).

Almost surely, 2^664999968 is an apocalyptic number.

It is an amenable number.

664999968 is an abundant number, since it is smaller than the sum of its proper divisors (1080625200).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

664999968 is a wasteful number, since it uses less digits than its factorization.

664999968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6927096 (or 6927088 counting only the distinct ones).

The product of its digits is 45349632, while the sum is 66.

The square root of 664999968 is about 25787.5932960019. The cubic root of 664999968 is about 872.8518595180.

It can be divided in two parts, 66499 and 9968, that added together give a palindrome (76467).

The spelling of 664999968 in words is "six hundred sixty-four million, nine hundred ninety-nine thousand, nine hundred sixty-eight".