21021220000 has 480 divisors, whose sum is σ = 61216404480. Its totient is φ = 7021440000.

The previous prime is 21021219883. The next prime is 21021220007. The reversal of 21021220000 is 2212012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (21021220007) 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 79 ways as a sum of consecutive naturals, for example, 196459947 + ... + 196460053.

It is an arithmetic number, because the mean of its divisors is an integer number (127534176).

Almost surely, 2^21021220000 is an apocalyptic number.

21021220000 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 21021220000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30608202240).

21021220000 is an abundant number, since it is smaller than the sum of its proper divisors (40195184480).

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

21021220000 is a wasteful number, since it uses less digits than its factorization.

21021220000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214 (or 191 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 21021220000 its reverse (2212012), we get a palindrome (21023432012).

The spelling of 21021220000 in words is "twenty-one billion, twenty-one million, two hundred twenty thousand".