165632720400 has 2025 divisors, whose sum is σ = 775259264439. Its totient is φ = 33756549120.

The previous prime is 165632720389. The next prime is 165632720401. The reversal of 165632720400 is 4027236561.

The square root of 165632720400 is 406980.

It is a perfect power (a square), and thus also a powerful number.

165632720400 is a `hidden beast` number, since 16 + 5 + 632 + 7 + 2 + 0 + 4 + 0 + 0 = 666.

165632720400 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 3874315536 + 161758404864 = 62244^2 + 402192^2 .

It is a tau number, because it is divible by the number of its divisors (2025).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (165632720401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 404 ways as a sum of consecutive naturals, for example, 8717511591 + ... + 8717511609.

Almost surely, 2^165632720400 is an apocalyptic number.

165632720400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

165632720400 is the 406980-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 165632720400

165632720400 is an abundant number, since it is smaller than the sum of its proper divisors (609626544039).

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

165632720400 is a wasteful number, since it uses less digits than its factorization.

165632720400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116 (or 53 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

Multiplying 165632720400 by its sum of digits (36), we get a square (5962777934400 = 2441880²).

165632720400 divided by its sum of digits (36) gives a square (4600908900 = 67830²).

Adding to 165632720400 its reverse (4027236561), we get a palindrome (169659956961).

The spelling of 165632720400 in words is "one hundred sixty-five billion, six hundred thirty-two million, seven hundred twenty thousand, four hundred".