20918211100 has 72 divisors (see below), whose sum is σ = 46022210640. Its totient is φ = 8251921920.

The previous prime is 20918211089. The next prime is 20918211107. The reversal of 20918211100 is 111281902.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20918211107) 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 23 ways as a sum of consecutive naturals, for example, 2446032 + ... + 2454568.

It is an arithmetic number, because the mean of its divisors is an integer number (639197370).

Almost surely, 2^20918211100 is an apocalyptic number.

20918211100 is a gapful number since it is divisible by the number (20) 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 20918211100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23011105320).

20918211100 is an abundant number, since it is smaller than the sum of its proper divisors (25103999540).

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

20918211100 is a wasteful number, since it uses less digits than its factorization.

20918211100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8887 (or 8880 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 25.

The spelling of 20918211100 in words is "twenty billion, nine hundred eighteen million, two hundred eleven thousand, one hundred".