664997768 has 16 divisors (see below), whose sum is σ = 1257906780. Its totient is φ = 329555968.

The previous prime is 664997717. The next prime is 664997813. The reversal of 664997768 is 867799466.

It can be written as a sum of positive squares in 2 ways, for example, as 458730724 + 206267044 = 21418^2 + 14362^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 664997768.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 366905 + ... + 368712.

Almost surely, 2^664997768 is an apocalyptic number.

It is an amenable number.

664997768 is a deficient number, since it is larger than the sum of its proper divisors (592909012).

664997768 is a wasteful number, since it uses less digits than its factorization.

664997768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 735736 (or 735732 counting only the distinct ones).

The product of its digits is 27433728, while the sum is 62.

The square root of 664997768 is about 25787.5506397952. The cubic root of 664997768 is about 872.8508969735.

The spelling of 664997768 in words is "six hundred sixty-four million, nine hundred ninety-seven thousand, seven hundred sixty-eight".