21021221200 has 60 divisors (see below), whose sum is σ = 57718275040. Its totient is φ = 7207274880.

The previous prime is 21021221183. The next prime is 21021221209. The reversal of 21021221200 is 212212012.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021221209) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3750990 + ... + 3756589.

Almost surely, 2^21021221200 is an apocalyptic number.

21021221200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021221200 is an abundant number, since it is smaller than the sum of its proper divisors (36697053840).

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

21021221200 is a wasteful number, since it uses less digits than its factorization.

21021221200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7507604 (or 7507593 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21021221200 its reverse (212212012), we get a palindrome (21233433212).

The spelling of 21021221200 in words is "twenty-one billion, twenty-one million, two hundred twenty-one thousand, two hundred".