21221111000000 has 784 divisors, whose sum is σ = 57126408772608. Its totient is φ = 7801305600000.

The previous prime is 21221110999961. The next prime is 21221111000021. The reversal of 21221111000000 is 11112212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 72426999854 + ... + 72427000146.

It is an arithmetic number, because the mean of its divisors is an integer number (72865317312).

Almost surely, 2^{21221111000000} is an apocalyptic number.

21221111000000 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 21221111000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28563204386304).

21221111000000 is an abundant number, since it is smaller than the sum of its proper divisors (35905297772608).

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

21221111000000 is an frugal number, since it uses more digits than its factorization.

21221111000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 472 (or 437 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21221111000000 its reverse (11112212), we get a palindrome (21221122112212).

The spelling of 21221111000000 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million", and thus it is an aban number.