21133311100 has 72 divisors (see below), whose sum is σ = 50172570000. Its totient is φ = 7662681600.

The previous prime is 21133311079. The next prime is 21133311151. The reversal of 21133311100 is 111333112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 356376 + ... + 411424.

It is an arithmetic number, because the mean of its divisors is an integer number (696841250).

Almost surely, 2^21133311100 is an apocalyptic number.

21133311100 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 21133311100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25086285000).

21133311100 is an abundant number, since it is smaller than the sum of its proper divisors (29039258900).

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

21133311100 is a wasteful number, since it uses less digits than its factorization.

21133311100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55423 (or 55416 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 16.

Adding to 21133311100 its reverse (111333112), we get a palindrome (21244644212).

It can be divided in two parts, 21133 and 311100, that added together give a palindrome (332233).

The spelling of 21133311100 in words is "twenty-one billion, one hundred thirty-three million, three hundred eleven thousand, one hundred".