20021009998 has 16 divisors (see below), whose sum is σ = 32764402944. Its totient is φ = 9099695160.

The previous prime is 20021009923. The next prime is 20021009999. The reversal of 20021009998 is 89990012002.

It is a self number, because there is not a number n which added to its sum of digits gives 20021009998.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021009999) 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 7 ways as a sum of consecutive naturals, for example, 294061 + ... + 355687.

It is an arithmetic number, because the mean of its divisors is an integer number (2047775184).

Almost surely, 2^20021009998 is an apocalyptic number.

20021009998 is a deficient number, since it is larger than the sum of its proper divisors (12743392946).

20021009998 is a wasteful number, since it uses less digits than its factorization.

20021009998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76407.

The product of its (nonzero) digits is 23328, while the sum is 40.

The spelling of 20021009998 in words is "twenty billion, twenty-one million, nine thousand, nine hundred ninety-eight".