21133221220 has 96 divisors (see below), whose sum is σ = 48635808480. Its totient is φ = 7681474560.

The previous prime is 21133221211. The next prime is 21133221229. The reversal of 21133221220 is 2212233112.

It is an interprime number because it is at equal distance from previous prime (21133221211) and next prime (21133221229).

It can be written as a sum of positive squares in 16 ways, for example, as 1261244196 + 19871977024 = 35514^2 + 140968^2 .

It is a super-3 number, since 3×21133221220³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (21133221229) 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 31 ways as a sum of consecutive naturals, for example, 1344366 + ... + 1359994.

It is an arithmetic number, because the mean of its divisors is an integer number (506623005).

Almost surely, 2^21133221220 is an apocalyptic number.

21133221220 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 21133221220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24317904240).

21133221220 is an abundant number, since it is smaller than the sum of its proper divisors (27502587260).

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

21133221220 is a wasteful number, since it uses less digits than its factorization.

21133221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15793 (or 15791 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21133221220 its reverse (2212233112), we get a palindrome (23345454332).

The spelling of 21133221220 in words is "twenty-one billion, one hundred thirty-three million, two hundred twenty-one thousand, two hundred twenty".