1665665566 has 8 divisors (see below), whose sum is σ = 2607128784. Its totient is φ = 796622640.

The previous prime is 1665665563. The next prime is 1665665581. The reversal of 1665665566 is 6655665661.

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 (1665665563) 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, 18105015 + ... + 18105106.

It is an arithmetic number, because the mean of its divisors is an integer number (325891098).

Almost surely, 2^1665665566 is an apocalyptic number.

1665665566 is a deficient number, since it is larger than the sum of its proper divisors (941463218).

1665665566 is a wasteful number, since it uses less digits than its factorization.

1665665566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36210146.

The product of its digits is 5832000, while the sum is 52.

The square root of 1665665566 is about 40812.5662755970. The cubic root of 1665665566 is about 1185.3936667339.

The spelling of 1665665566 in words is "one billion, six hundred sixty-five million, six hundred sixty-five thousand, five hundred sixty-six".