666405776 has 20 divisors (see below), whose sum is σ = 1291761072. Its totient is φ = 333048096.

The previous prime is 666405757. The next prime is 666405781. The reversal of 666405776 is 677504666.

It is a hoax number, since the sum of its digits (47) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 666405776.

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, 31031 + ... + 47913.

Almost surely, 2^666405776 is an apocalyptic number.

It is an amenable number.

666405776 is a deficient number, since it is larger than the sum of its proper divisors (625355296).

666405776 is a wasteful number, since it uses less digits than its factorization.

666405776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19358 (or 19352 counting only the distinct ones).

The product of its (nonzero) digits is 1270080, while the sum is 47.

The square root of 666405776 is about 25814.8363543138. The cubic root of 666405776 is about 873.4664953733.

The spelling of 666405776 in words is "six hundred sixty-six million, four hundred five thousand, seven hundred seventy-six".