165809280 has 384 divisors, whose sum is σ = 663016320. Its totient is φ = 34504704.

The previous prime is 165809251. The next prime is 165809291. The reversal of 165809280 is 82908561.

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

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2271324 + ... + 2271396.

It is an arithmetic number, because the mean of its divisors is an integer number (1726605).

Almost surely, 2^165809280 is an apocalyptic number.

165809280 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 165809280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (331508160).

165809280 is an abundant number, since it is smaller than the sum of its proper divisors (497207040).

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

165809280 is a wasteful number, since it uses less digits than its factorization.

165809280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128 (or 103 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 39.

The square root of 165809280 is about 12876.6952282020. The cubic root of 165809280 is about 549.3759091853.

The spelling of 165809280 in words is "one hundred sixty-five million, eight hundred nine thousand, two hundred eighty".