21001443100 has 72 divisors (see below), whose sum is σ = 49900306176. Its totient is φ = 7608600000.

The previous prime is 21001443077. The next prime is 21001443107. The reversal of 21001443100 is 134410012.

It is a super-2 number, since 2×21001443100² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001443107) 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, 262875 + ... + 333325.

It is an arithmetic number, because the mean of its divisors is an integer number (693059808).

Almost surely, 2^21001443100 is an apocalyptic number.

21001443100 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 21001443100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24950153088).

21001443100 is an abundant number, since it is smaller than the sum of its proper divisors (28898863076).

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

21001443100 is a wasteful number, since it uses less digits than its factorization.

21001443100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70747 (or 70740 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21001443100 its reverse (134410012), we get a palindrome (21135853112).

The spelling of 21001443100 in words is "twenty-one billion, one million, four hundred forty-three thousand, one hundred".