1665966720 has 384 divisors, whose sum is σ = 5977722240. Its totient is φ = 394240000.

The previous prime is 1665966719. The next prime is 1665966733. The reversal of 1665966720 is 276695661.

1665966720 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-2 number, since 2×1665966720² = 5550890224295116800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 1665966720.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 16494670 + ... + 16494770.

It is an arithmetic number, because the mean of its divisors is an integer number (15566985).

Almost surely, 2^1665966720 is an apocalyptic number.

1665966720 is a gapful number since it is divisible by the number (10) 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 1665966720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2988861120).

1665966720 is an abundant number, since it is smaller than the sum of its proper divisors (4311755520).

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

1665966720 is a wasteful number, since it uses less digits than its factorization.

1665966720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216 (or 193 counting only the distinct ones).

The product of its (nonzero) digits is 816480, while the sum is 48.

The square root of 1665966720 is about 40816.2555852445. The cubic root of 1665966720 is about 1185.4651025490.

The spelling of 1665966720 in words is "one billion, six hundred sixty-five million, nine hundred sixty-six thousand, seven hundred twenty".