21221213323200 has 336 divisors, whose sum is σ = 75978348074496. Its totient is φ = 5142796083200.

The previous prime is 21221213323199. The next prime is 21221213323217. The reversal of 21221213323200 is 232331212212.

It is a super-2 number, since 2×21221213323200² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 159547924 + ... + 159680876.

It is an arithmetic number, because the mean of its divisors is an integer number (226126035936).

Almost surely, 2^{21221213323200} is an apocalyptic number.

21221213323200 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 21221213323200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37989174037248).

21221213323200 is an abundant number, since it is smaller than the sum of its proper divisors (54757134751296).

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

21221213323200 is a wasteful number, since it uses less digits than its factorization.

21221213323200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136012 (or 135997 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 24.

Adding to 21221213323200 its reverse (232331212212), we get a palindrome (21453544535412).

The spelling of 21221213323200 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred thirteen million, three hundred twenty-three thousand, two hundred".