21231021330 has 72 divisors (see below), whose sum is σ = 56121304356. Its totient is φ = 5568704640.

The previous prime is 21231021281. The next prime is 21231021337. The reversal of 21231021330 is 3312013212.

21231021330 is a `hidden beast` number, since 2 + 1 + 2 + 310 + 21 + 330 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 45927729 + 21185093601 = 6777^2 + 145551^2 .

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21231021337) 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 35 ways as a sum of consecutive naturals, for example, 303192 + ... + 366588.

Almost surely, 2^21231021330 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21231021330, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28060652178).

21231021330 is an abundant number, since it is smaller than the sum of its proper divisors (34890283026).

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

21231021330 is a wasteful number, since it uses less digits than its factorization.

21231021330 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63532 (or 63468 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

Adding to 21231021330 its reverse (3312013212), we get a palindrome (24543034542).

The spelling of 21231021330 in words is "twenty-one billion, two hundred thirty-one million, twenty-one thousand, three hundred thirty".