9921688018 has 8 divisors (see below), whose sum is σ = 16235489520.
Its totient is φ = 4509858180.
The previous prime is 9921688013. The next prime is 9921688057. The reversal of 9921688018 is 8108861299.
9921688018 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a sphenic number, since it is the product of 3 distinct primes.
It is not an unprimeable number, because it can be changed into a prime (9921688013) 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 3 ways as a sum of consecutive naturals, for example, 225492888 + ... + 225492931.
It is an arithmetic number, because the mean of its divisors is an integer number (2029436190).
Almost surely, 29921688018 is an apocalyptic number.
9921688018 is a deficient number, since it is larger than the sum of its proper divisors (6313801502).
9921688018 is a wasteful number, since it uses less digits than its factorization.
9921688018 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 450985832.
The product of its (nonzero) digits is 497664, while the sum is 52.
The square root of 9921688018 is about 99607.6704777298.
The cubic root of 9921688018 is about 2148.7960100868.
The spelling of 9921688018 in words is "nine billion, nine hundred twenty-one million, six hundred eighty-eight thousand, eighteen".