165536521800 has 384 divisors, whose sum is σ = 581272796160. Its totient is φ = 38686003200.

The previous prime is 165536521793. The next prime is 165536521811. The reversal of 165536521800 is 8125635561.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 12808942 + ... + 12821858.

It is an arithmetic number, because the mean of its divisors is an integer number (1513731240).

Almost surely, 2^165536521800 is an apocalyptic number.

165536521800 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 165536521800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (290636398080).

165536521800 is an abundant number, since it is smaller than the sum of its proper divisors (415736274360).

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

165536521800 is a wasteful number, since it uses less digits than its factorization.

165536521800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13033 (or 13024 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 42.

The spelling of 165536521800 in words is "one hundred sixty-five billion, five hundred thirty-six million, five hundred twenty-one thousand, eight hundred".