1665705888 has 288 divisors, whose sum is σ = 6098706432. Its totient is φ = 418521600.

The previous prime is 1665705871. The next prime is 1665705907. The reversal of 1665705888 is 8885075661.

1665705888 is a `hidden beast` number, since 1 + 6 + 6 + 57 + 0 + 588 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×1665705888² = 5549152210635737088, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 686245 + ... + 688667.

It is an arithmetic number, because the mean of its divisors is an integer number (21176064).

Almost surely, 2^1665705888 is an apocalyptic number.

1665705888 is a gapful number since it is divisible by the number (18) 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 1665705888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3049353216).

1665705888 is an abundant number, since it is smaller than the sum of its proper divisors (4433000544).

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

1665705888 is a wasteful number, since it uses less digits than its factorization.

1665705888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2488 (or 2477 counting only the distinct ones).

The product of its (nonzero) digits is 3225600, while the sum is 54.

The square root of 1665705888 is about 40813.0602626169. The cubic root of 1665705888 is about 1185.4032318909.

The spelling of 1665705888 in words is "one billion, six hundred sixty-five million, seven hundred five thousand, eight hundred eighty-eight".