1666643404 has 12 divisors (see below), whose sum is σ = 2924324200. Its totient is φ = 831122208.

The previous prime is 1666643401. The next prime is 1666643431. The reversal of 1666643404 is 4043466661.

It is not an unprimeable number, because it can be changed into a prime (1666643401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 548169 + ... + 551200.

Almost surely, 2^1666643404 is an apocalyptic number.

It is an amenable number.

1666643404 is a deficient number, since it is larger than the sum of its proper divisors (1257680796).

1666643404 is a wasteful number, since it uses less digits than its factorization.

1666643404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1099752 (or 1099750 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 40.

The square root of 1666643404 is about 40824.5441370752. The cubic root of 1666643404 is about 1185.6255852828.

The spelling of 1666643404 in words is "one billion, six hundred sixty-six million, six hundred forty-three thousand, four hundred four".