1664405566 has 8 divisors (see below), whose sum is σ = 2515666824. Its totient is φ = 825849960.

The previous prime is 1664405539. The next prime is 1664405569. The reversal of 1664405566 is 6655044661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664405569) 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, 3176085 + ... + 3176608.

It is an arithmetic number, because the mean of its divisors is an integer number (314458353).

Almost surely, 2^1664405566 is an apocalyptic number.

1664405566 is a deficient number, since it is larger than the sum of its proper divisors (851261258).

1664405566 is a wasteful number, since it uses less digits than its factorization.

1664405566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6352826.

The product of its (nonzero) digits is 518400, while the sum is 43.

The square root of 1664405566 is about 40797.1269331555. The cubic root of 1664405566 is about 1185.0946925938.

The spelling of 1664405566 in words is "one billion, six hundred sixty-four million, four hundred five thousand, five hundred sixty-six".