1665171648 has 448 divisors, whose sum is σ = 5969203200. Its totient is φ = 445132800.

The previous prime is 1665171631. The next prime is 1665171653. The reversal of 1665171648 is 8461715661.

It is a tau number, because it is divible by the number of its divisors (448).

Its product of digits (241920) is a multiple of the sum of its prime divisors (189).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 16486798 + ... + 16486898.

Almost surely, 2^1665171648 is an apocalyptic number.

1665171648 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 1665171648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2984601600).

1665171648 is an abundant number, since it is smaller than the sum of its proper divisors (4304031552).

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

1665171648 is a wasteful number, since it uses less digits than its factorization.

1665171648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205 (or 189 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

The square root of 1665171648 is about 40806.5147739917. The cubic root of 1665171648 is about 1185.2764873189.

The spelling of 1665171648 in words is "one billion, six hundred sixty-five million, one hundred seventy-one thousand, six hundred forty-eight".