1666265565 has 32 divisors (see below), whose sum is σ = 2707689600. Its totient is φ = 874874880.

The previous prime is 1666265563. The next prime is 1666265581. The reversal of 1666265565 is 5655626661.

It is not a de Polignac number, because 1666265565 - 2¹ = 1666265563 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666265563) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 319146 + ... + 324324.

It is an arithmetic number, because the mean of its divisors is an integer number (84615300).

Almost surely, 2^1666265565 is an apocalyptic number.

1666265565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1666265565 is a deficient number, since it is larger than the sum of its proper divisors (1041424035).

1666265565 is a wasteful number, since it uses less digits than its factorization.

1666265565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5517.

The product of its digits is 1944000, while the sum is 48.

The square root of 1666265565 is about 40819.9162786991. The cubic root of 1666265565 is about 1185.5359821436.

The spelling of 1666265565 in words is "one billion, six hundred sixty-six million, two hundred sixty-five thousand, five hundred sixty-five".