21200121200 has 120 divisors (see below), whose sum is σ = 53225069568. Its totient is φ = 8099562240.

The previous prime is 21200121197. The next prime is 21200121203. The reversal of 21200121200 is 212100212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21200121197) and next prime (21200121203).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200121203) 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 23 ways as a sum of consecutive naturals, for example, 8895209 + ... + 8897591.

Almost surely, 2^21200121200 is an apocalyptic number.

21200121200 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 21200121200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26612534784).

21200121200 is an abundant number, since it is smaller than the sum of its proper divisors (32024948368).

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

21200121200 is a wasteful number, since it uses less digits than its factorization.

21200121200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3391 (or 3380 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21200121200 its reverse (212100212), we get a palindrome (21412221412).

It can be divided in two parts, 2120012 and 1200, that added together give a palindrome (2121212).

The spelling of 21200121200 in words is "twenty-one billion, two hundred million, one hundred twenty-one thousand, two hundred".