165999204900 has 243 divisors, whose sum is σ = 541376250961. Its totient is φ = 44178449760.

The previous prime is 165999204881. The next prime is 165999204937. The reversal of 165999204900 is 9402999561.

The square root of 165999204900 is 407430.

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

165999204900 is a `hidden beast` number, since 1 + 6 + 599 + 9 + 2 + 0 + 49 + 0 + 0 = 666.

It can be written as a sum of positive squares in only one way, i.e., 59759713764 + 106239491136 = 244458^2 + 325944^2 .

It is a tau number, because it is divible by the number of its divisors (243).

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Duffinian number.

It is an unprimeable number.

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 80 ways as a sum of consecutive naturals, for example, 330018049 + ... + 330018551.

Almost surely, 2^165999204900 is an apocalyptic number.

165999204900 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

165999204900 is the 407430-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 165999204900

165999204900 is an abundant number, since it is smaller than the sum of its proper divisors (375377046061).

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

165999204900 is an frugal number, since it uses more digits than its factorization.

165999204900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1044 (or 513 counting only the distinct ones).

The product of its (nonzero) digits is 1574640, while the sum is 54.

The spelling of 165999204900 in words is "one hundred sixty-five billion, nine hundred ninety-nine million, two hundred four thousand, nine hundred".