198042721668 has 288 divisors, whose sum is σ = 582894434304. Its totient is φ = 56572824000.

The previous prime is 198042721661. The next prime is 198042721693. The reversal of 198042721668 is 866127240891.

It is a happy number.

198042721668 is a `hidden beast` number, since 198 + 0 + 427 + 21 + 6 + 6 + 8 = 666.

It is not an unprimeable number, because it can be changed into a prime (198042721661) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 78245563 + ... + 78248093.

It is an arithmetic number, because the mean of its divisors is an integer number (2023939008).

Almost surely, 2^198042721668 is an apocalyptic number.

198042721668 is a gapful number since it is divisible by the number (18) 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 198042721668, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (291447217152).

198042721668 is an abundant number, since it is smaller than the sum of its proper divisors (384851712636).

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

198042721668 is a wasteful number, since it uses less digits than its factorization.

198042721668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2668 (or 2641 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 54.

It can be divided in two parts, 19804 and 2721668, that added together give a palindrome (2741472).

The spelling of 198042721668 in words is "one hundred ninety-eight billion, forty-two million, seven hundred twenty-one thousand, six hundred sixty-eight".