21103001220 has 96 divisors (see below), whose sum is σ = 67695264000. Its totient is φ = 4811710464.

The previous prime is 21103001219. The next prime is 21103001237. The reversal of 21103001220 is 2210030112.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21103001196 and 21103001205.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 110356 + ... + 233204.

It is an arithmetic number, because the mean of its divisors is an integer number (705159000).

Almost surely, 2^21103001220 is an apocalyptic number.

21103001220 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 21103001220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33847632000).

21103001220 is an abundant number, since it is smaller than the sum of its proper divisors (46592262780).

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

21103001220 is a wasteful number, since it uses less digits than its factorization.

21103001220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123277 (or 123275 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21103001220 its reverse (2210030112), we get a palindrome (23313031332).

The spelling of 21103001220 in words is "twenty-one billion, one hundred three million, one thousand, two hundred twenty".