21311003220 has 192 divisors, whose sum is σ = 68276113920. Its totient is φ = 4927813632.

The previous prime is 21311003149. The next prime is 21311003221. The reversal of 21311003220 is 2230011312.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21311003220.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311003221) 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 63 ways as a sum of consecutive naturals, for example, 824209 + ... + 849671.

It is an arithmetic number, because the mean of its divisors is an integer number (355604760).

Almost surely, 2^21311003220 is an apocalyptic number.

21311003220 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 21311003220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34138056960).

21311003220 is an abundant number, since it is smaller than the sum of its proper divisors (46965110700).

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

21311003220 is a wasteful number, since it uses less digits than its factorization.

21311003220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25554 (or 25552 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21311003220 its reverse (2230011312), we get a palindrome (23541014532).

The spelling of 21311003220 in words is "twenty-one billion, three hundred eleven million, three thousand, two hundred twenty".