21120101220 has 96 divisors (see below), whose sum is σ = 60980887296. Its totient is φ = 5458176000.

The previous prime is 21120101207. The next prime is 21120101221. The reversal of 21120101220 is 2210102112.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21120101196 and 21120101205.

It is not an unprimeable number, because it can be changed into a prime (21120101221) 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, 343032 + ... + 399888.

It is an arithmetic number, because the mean of its divisors is an integer number (635217576).

Almost surely, 2^21120101220 is an apocalyptic number.

21120101220 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 21120101220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30490443648).

21120101220 is an abundant number, since it is smaller than the sum of its proper divisors (39860786076).

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

21120101220 is a wasteful number, since it uses less digits than its factorization.

21120101220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57061 (or 57059 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21120101220 its reverse (2210102112), we get a palindrome (23330203332).

The spelling of 21120101220 in words is "twenty-one billion, one hundred twenty million, one hundred one thousand, two hundred twenty".