21201221120 has 80 divisors (see below), whose sum is σ = 51792689520. Its totient is φ = 8320425984.

The previous prime is 21201221089. The next prime is 21201221137. The reversal of 21201221120 is 2112210212.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 21201221095 and 21201221104.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57551 + ... + 213809.

It is an arithmetic number, because the mean of its divisors is an integer number (647408619).

Almost surely, 2^21201221120 is an apocalyptic number.

21201221120 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 21201221120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25896344760).

21201221120 is an abundant number, since it is smaller than the sum of its proper divisors (30591468400).

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

21201221120 is an equidigital number, since it uses as much as digits as its factorization.

21201221120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156335 (or 156319 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21201221120 its reverse (2112210212), we get a palindrome (23313431332).

It can be divided in two parts, 2120 and 1221120, that multiplied together give a square (2588774400 = 50880²).

The spelling of 21201221120 in words is "twenty-one billion, two hundred one million, two hundred twenty-one thousand, one hundred twenty".