21220312032 has 144 divisors (see below), whose sum is σ = 63659756160. Its totient is φ = 6686551296.

The previous prime is 21220312031. The next prime is 21220312037. The reversal of 21220312032 is 23021302212.

It is a tau number, because it is divible by the number of its divisors (144).

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

It is a junction number, because it is equal to n+sod(n) for n = 21220311996 and 21220312014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220312031) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2660883 + ... + 2668845.

It is an arithmetic number, because the mean of its divisors is an integer number (442081640).

Almost surely, 2^21220312032 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21220312032, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31829878080).

21220312032 is an abundant number, since it is smaller than the sum of its proper divisors (42439444128).

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

21220312032 is a wasteful number, since it uses less digits than its factorization.

21220312032 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8485 (or 8474 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

Adding to 21220312032 its reverse (23021302212), we get a palindrome (44241614244).

The spelling of 21220312032 in words is "twenty-one billion, two hundred twenty million, three hundred twelve thousand, thirty-two".