165818320920 has 192 divisors, whose sum is σ = 619301067840. Its totient is φ = 37691827200.

The previous prime is 165818320919. The next prime is 165818320951. The reversal of 165818320920 is 29023818561.

165818320920 is a `hidden beast` number, since 16 + 581 + 8 + 32 + 0 + 9 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

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, 274350 + ... + 637890.

It is an arithmetic number, because the mean of its divisors is an integer number (3225526395).

Almost surely, 2^165818320920 is an apocalyptic number.

165818320920 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 165818320920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (309650533920).

165818320920 is an abundant number, since it is smaller than the sum of its proper divisors (453482746920).

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

165818320920 is a wasteful number, since it uses less digits than its factorization.

165818320920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 363746 (or 363739 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The spelling of 165818320920 in words is "one hundred sixty-five billion, eight hundred eighteen million, three hundred twenty thousand, nine hundred twenty".