1665668736 has 96 divisors (see below), whose sum is σ = 4883750820. Its totient is φ = 544727040.

The previous prime is 1665668699. The next prime is 1665668759. The reversal of 1665668736 is 6378665661.

1665668736 is a `hidden beast` number, since 1 + 6 + 6 + 566 + 8 + 73 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1558670400 + 106998336 = 39480^2 + 10344^2 .

It is a tau number, because it is divible by the number of its divisors (96).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 47416 + ... + 74696.

Almost surely, 2^1665668736 is an apocalyptic number.

1665668736 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1665668736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2441875410).

1665668736 is an abundant number, since it is smaller than the sum of its proper divisors (3218082084).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1665668736 is a wasteful number, since it uses less digits than its factorization.

1665668736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27354 (or 27339 counting only the distinct ones).

The product of its digits is 6531840, while the sum is 54.

The square root of 1665668736 is about 40812.6051116564. The cubic root of 1665668736 is about 1185.3944187247.

The spelling of 1665668736 in words is "one billion, six hundred sixty-five million, six hundred sixty-eight thousand, seven hundred thirty-six".