21021331100 has 144 divisors (see below), whose sum is σ = 56966353920. Its totient is φ = 6541267200.

The previous prime is 21021331099. The next prime is 21021331139. The reversal of 21021331100 is 113312012.

It is a super-2 number, since 2×21021331100² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 5534402 + ... + 5538198.

It is an arithmetic number, because the mean of its divisors is an integer number (395599680).

Almost surely, 2^21021331100 is an apocalyptic number.

21021331100 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 21021331100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28483176960).

21021331100 is an abundant number, since it is smaller than the sum of its proper divisors (35945022820).

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

21021331100 is a wasteful number, since it uses less digits than its factorization.

21021331100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4548 (or 4541 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 14.

Adding to 21021331100 its reverse (113312012), we get a palindrome (21134643112).

The spelling of 21021331100 in words is "twenty-one billion, twenty-one million, three hundred thirty-one thousand, one hundred".