21021331200 has 216 divisors, whose sum is σ = 70258003200. Its totient is φ = 5534330880.

The previous prime is 21021331189. The next prime is 21021331213. The reversal of 21021331200 is 213312012.

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 21021331200.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1509871 + ... + 1523729.

Almost surely, 2^21021331200 is an apocalyptic number.

21021331200 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 21021331200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35129001600).

21021331200 is an abundant number, since it is smaller than the sum of its proper divisors (49236672000).

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

21021331200 is a wasteful number, since it uses less digits than its factorization.

21021331200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13967 (or 13948 counting only the distinct ones).

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

Adding to 21021331200 its reverse (213312012), we get a palindrome (21234643212).

The spelling of 21021331200 in words is "twenty-one billion, twenty-one million, three hundred thirty-one thousand, two hundred".