661266664 has 16 divisors (see below), whose sum is σ = 1273385700. Its totient is φ = 321697152.

The previous prime is 661266607. The next prime is 661266679. The reversal of 661266664 is 466662166.

It can be written as a sum of positive squares in 2 ways, for example, as 648720900 + 12545764 = 25470^2 + 3542^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 661266664.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1116709 + ... + 1117300.

Almost surely, 2^661266664 is an apocalyptic number.

It is an amenable number.

661266664 is a deficient number, since it is larger than the sum of its proper divisors (612119036).

661266664 is a wasteful number, since it uses less digits than its factorization.

661266664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2234052 (or 2234048 counting only the distinct ones).

The product of its digits is 373248, while the sum is 43.

The square root of 661266664 is about 25715.1057551782. The cubic root of 661266664 is about 871.2153990953.

The spelling of 661266664 in words is "six hundred sixty-one million, two hundred sixty-six thousand, six hundred sixty-four".