199791368820 has 144 divisors (see below), whose sum is σ = 641842503120. Its totient is φ = 50131243008.

The previous prime is 199791368779. The next prime is 199791368827. The reversal of 199791368820 is 28863197991.

199791368820 is a `hidden beast` number, since 199 + 7 + 9 + 1 + 368 + 82 + 0 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 1278348516 + 198513020304 = 35754^2 + 445548^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199791368827) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22361074 + ... + 22370006.

It is an arithmetic number, because the mean of its divisors is an integer number (4457239605).

Almost surely, 2^199791368820 is an apocalyptic number.

199791368820 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 199791368820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (320921251560).

199791368820 is an abundant number, since it is smaller than the sum of its proper divisors (442051134300).

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

199791368820 is a wasteful number, since it uses less digits than its factorization.

199791368820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16274 (or 16269 counting only the distinct ones).

The product of its (nonzero) digits is 11757312, while the sum is 63.

The spelling of 199791368820 in words is "one hundred ninety-nine billion, seven hundred ninety-one million, three hundred sixty-eight thousand, eight hundred twenty".