21002132220 has 192 divisors, whose sum is σ = 63334656000. Its totient is φ = 5184241920.

The previous prime is 21002132167. The next prime is 21002132233. The reversal of 21002132220 is 2223120012.

It is a happy number.

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 21002132220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 10004731 + ... + 10006829.

It is an arithmetic number, because the mean of its divisors is an integer number (329868000).

Almost surely, 2^21002132220 is an apocalyptic number.

21002132220 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 21002132220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31667328000).

21002132220 is an abundant number, since it is smaller than the sum of its proper divisors (42332523780).

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

21002132220 is a wasteful number, since it uses less digits than its factorization.

21002132220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2328 (or 2326 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

Adding to 21002132220 its reverse (2223120012), we get a palindrome (23225252232).

The spelling of 21002132220 in words is "twenty-one billion, two million, one hundred thirty-two thousand, two hundred twenty".