1665443520 has 168 divisors, whose sum is σ = 6169219056. Its totient is φ = 409946112.

The previous prime is 1665443489. The next prime is 1665443531. The reversal of 1665443520 is 253445661.

1665443520 is a `hidden beast` number, since 1 + 66 + 544 + 3 + 52 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15199 + ... + 59681.

It is an arithmetic number, because the mean of its divisors is an integer number (36721542).

Almost surely, 2^1665443520 is an apocalyptic number.

1665443520 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 1665443520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3084609528).

1665443520 is an abundant number, since it is smaller than the sum of its proper divisors (4503775536).

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

1665443520 is a wasteful number, since it uses less digits than its factorization.

1665443520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44519 (or 44506 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 1665443520 is about 40809.8458708190. The cubic root of 1665443520 is about 1185.3409903695.

The spelling of 1665443520 in words is "one billion, six hundred sixty-five million, four hundred forty-three thousand, five hundred twenty".