21201212021200 has 120 divisors (see below), whose sum is σ = 52582555731200. Its totient is φ = 8206366694400.

The previous prime is 21201212021177. The next prime is 21201212021201. The reversal of 21201212021200 is 212021210212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201212021201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 216318607 + ... + 216416593.

Almost surely, 2^{21201212021200} is an apocalyptic number.

21201212021200 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 21201212021200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26291277865600).

21201212021200 is an abundant number, since it is smaller than the sum of its proper divisors (31381343710000).

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

21201212021200 is a wasteful number, since it uses less digits than its factorization.

21201212021200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115485 (or 115474 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21201212021200 its reverse (212021210212), we get a palindrome (21413233231412).

The spelling of 21201212021200 in words is "twenty-one trillion, two hundred one billion, two hundred twelve million, twenty-one thousand, two hundred".