648809666 has 24 divisors (see below), whose sum is σ = 1014581484. Its totient is φ = 310991360.

The previous prime is 648809657. The next prime is 648809677. The reversal of 648809666 is 666908846.

It can be written as a sum of positive squares in 2 ways, for example, as 646634041 + 2175625 = 25429^2 + 1475^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 284306 + ... + 286578.

Almost surely, 2^648809666 is an apocalyptic number.

648809666 is a deficient number, since it is larger than the sum of its proper divisors (365771818).

648809666 is a wasteful number, since it uses less digits than its factorization.

648809666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2434 (or 2375 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 53.

The square root of 648809666 is about 25471.7425002688. The cubic root of 648809666 is about 865.7100058943.

The spelling of 648809666 in words is "six hundred forty-eight million, eight hundred nine thousand, six hundred sixty-six".