21211222021200 has 480 divisors, whose sum is σ = 78799336876800. Its totient is φ = 5408980346880.

The previous prime is 21211222021141. The next prime is 21211222021211. The reversal of 21211222021200 is 212022211212.

It is a happy number.

21211222021200 is a `hidden beast` number, since 21 + 211 + 2 + 220 + 212 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1211438046 + ... + 1211455554.

It is an arithmetic number, because the mean of its divisors is an integer number (164165285160).

Almost surely, 2^{21211222021200} is an apocalyptic number.

21211222021200 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 21211222021200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39399668438400).

21211222021200 is an abundant number, since it is smaller than the sum of its proper divisors (57588114855600).

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

21211222021200 is a wasteful number, since it uses less digits than its factorization.

21211222021200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22436 (or 22419 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21211222021200 its reverse (212022211212), we get a palindrome (21423244232412).

The spelling of 21211222021200 in words is "twenty-one trillion, two hundred eleven billion, two hundred twenty-two million, twenty-one thousand, two hundred".