21000441220 has 96 divisors (see below), whose sum is σ = 51598270080. Its totient is φ = 7098024960.

The previous prime is 21000441193. The next prime is 21000441233. The reversal of 21000441220 is 2214400012.

It is a junction number, because it is equal to n+sod(n) for n = 21000441194 and 21000441203.

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 31 ways as a sum of consecutive naturals, for example, 174144 + ... + 268936.

It is an arithmetic number, because the mean of its divisors is an integer number (537481980).

Almost surely, 2^21000441220 is an apocalyptic number.

21000441220 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 21000441220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25799135040).

21000441220 is an abundant number, since it is smaller than the sum of its proper divisors (30597828860).

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

21000441220 is a wasteful number, since it uses less digits than its factorization.

21000441220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94885 (or 94883 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 21000441220 its reverse (2214400012), we get a palindrome (23214841232).

The spelling of 21000441220 in words is "twenty-one billion, four hundred forty-one thousand, two hundred twenty".