165999560 has 64 divisors (see below), whose sum is σ = 399550320. Its totient is φ = 61849600.

The previous prime is 165999553. The next prime is 165999569. The reversal of 165999560 is 65999561.

It can be written as a sum of positive squares in 8 ways, for example, as 164198596 + 1800964 = 12814^2 + 1342^2 .

It is a junction number, because it is equal to n+sod(n) for n = 165999499 and 165999508.

It is not an unprimeable number, because it can be changed into a prime (165999569) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67472 + ... + 69888.

Almost surely, 2^165999560 is an apocalyptic number.

165999560 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 165999560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (199775160).

165999560 is an abundant number, since it is smaller than the sum of its proper divisors (233550760).

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

165999560 is a wasteful number, since it uses less digits than its factorization.

165999560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2546 (or 2542 counting only the distinct ones).

The product of its (nonzero) digits is 656100, while the sum is 50.

The square root of 165999560 is about 12884.0816514022. The cubic root of 165999560 is about 549.5859804307.

Subtracting from 165999560 its reverse (65999561), we obtain a palindrome (99999999).

The spelling of 165999560 in words is "one hundred sixty-five million, nine hundred ninety-nine thousand, five hundred sixty".