21321220120 has 64 divisors (see below), whose sum is σ = 50583852000. Its totient is φ = 8065824768.

The previous prime is 21321220103. The next prime is 21321220127. The reversal of 21321220120 is 2102212312.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21321220094 and 21321220103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321220127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 427026 + ... + 474334.

Almost surely, 2^21321220120 is an apocalyptic number.

21321220120 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 21321220120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25291926000).

21321220120 is an abundant number, since it is smaller than the sum of its proper divisors (29262631880).

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

21321220120 is a wasteful number, since it uses less digits than its factorization.

21321220120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47932 (or 47928 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21321220120 its reverse (2102212312), we get a palindrome (23423432432).

It can be divided in two parts, 213212 and 20120, that added together give a palindrome (233332).

The spelling of 21321220120 in words is "twenty-one billion, three hundred twenty-one million, two hundred twenty thousand, one hundred twenty".