1665450666 has 64 divisors (see below), whose sum is σ = 4088678400. Its totient is φ = 498279600.

The previous prime is 1665450659. The next prime is 1665450671. The reversal of 1665450666 is 6660545661.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

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 31 ways as a sum of consecutive naturals, for example, 29181 + ... + 64671.

It is an arithmetic number, because the mean of its divisors is an integer number (63885600).

Almost surely, 2^1665450666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1665450666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2044339200).

1665450666 is an abundant number, since it is smaller than the sum of its proper divisors (2423227734).

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

1665450666 is a wasteful number, since it uses less digits than its factorization.

1665450666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35592 (or 35586 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 45.

The square root of 1665450666 is about 40809.9334231263. The cubic root of 1665450666 is about 1185.3426857006.

The spelling of 1665450666 in words is "one billion, six hundred sixty-five million, four hundred fifty thousand, six hundred sixty-six".