165791220 has 96 divisors (see below), whose sum is σ = 532224000. Its totient is φ = 37774464.

The previous prime is 165791209. The next prime is 165791221. The reversal of 165791220 is 22197561.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165791221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 251251 + ... + 251909.

It is an arithmetic number, because the mean of its divisors is an integer number (5544000).

Almost surely, 2^165791220 is an apocalyptic number.

165791220 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 165791220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (266112000).

165791220 is an abundant number, since it is smaller than the sum of its proper divisors (366432780).

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

165791220 is a wasteful number, since it uses less digits than its factorization.

165791220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1277 (or 1275 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 33.

The square root of 165791220 is about 12875.9939422167. The cubic root of 165791220 is about 549.3559623943.

The spelling of 165791220 in words is "one hundred sixty-five million, seven hundred ninety-one thousand, two hundred twenty".