21122120220 has 96 divisors (see below), whose sum is σ = 63078378048. Its totient is φ = 5262508032.

The previous prime is 21122120209. The next prime is 21122120231. The reversal of 21122120220 is 2202122112.

It is an interprime number because it is at equal distance from previous prime (21122120209) and next prime (21122120231).

It is a super-2 number, since 2×21122120220² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21122120220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 64164 + ... + 215316.

It is an arithmetic number, because the mean of its divisors is an integer number (657066438).

Almost surely, 2^21122120220 is an apocalyptic number.

21122120220 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 21122120220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31539189024).

21122120220 is an abundant number, since it is smaller than the sum of its proper divisors (41956257828).

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

21122120220 is a wasteful number, since it uses less digits than its factorization.

21122120220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151319 (or 151317 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21122120220 its reverse (2202122112), we get a palindrome (23324242332).

The spelling of 21122120220 in words is "twenty-one billion, one hundred twenty-two million, one hundred twenty thousand, two hundred twenty".