21212001221120 has 160 divisors (see below), whose sum is σ = 51436589128848. Its totient is φ = 8388637360128.

The previous prime is 21212001221083. The next prime is 21212001221141. The reversal of 21212001221120 is 2112210021212.

It can be written as a sum of positive squares in 8 ways, for example, as 17142647175424 + 4069354045696 = 4140368^2 + 2017264^2 .

It is a tau number, because it is divible by the number of its divisors (160).

It is a super-2 number, since 2×21212001221120² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 242564924 + ... + 242652356.

Almost surely, 2^{21212001221120} is an apocalyptic number.

21212001221120 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 21212001221120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25718294564424).

21212001221120 is an abundant number, since it is smaller than the sum of its proper divisors (30224587907728).

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

21212001221120 is an frugal number, since it uses more digits than its factorization.

21212001221120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88530 (or 88514 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21212001221120 its reverse (2112210021212), we get a palindrome (23324211242332).

The spelling of 21212001221120 in words is "twenty-one trillion, two hundred twelve billion, one million, two hundred twenty-one thousand, one hundred twenty".