21222222001220 has 96 divisors (see below), whose sum is σ = 46041877018368. Its totient is φ = 8212053975552.

The previous prime is 21222222001199. The next prime is 21222222001261. The reversal of 21222222001220 is 2210022222212.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21222222001192 and 21222222001201.

It is an unprimeable number.

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, 39516014 + ... + 40049466.

It is an arithmetic number, because the mean of its divisors is an integer number (479602885608).

Almost surely, 2^{21222222001220} is an apocalyptic number.

21222222001220 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 21222222001220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23020938509184).

21222222001220 is an abundant number, since it is smaller than the sum of its proper divisors (24819655017148).

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

21222222001220 is a wasteful number, since it uses less digits than its factorization.

21222222001220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 533949 (or 533947 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 21222222001220 its reverse (2210022222212), we get a palindrome (23432244223432).

The spelling of 21222222001220 in words is "twenty-one trillion, two hundred twenty-two billion, two hundred twenty-two million, one thousand, two hundred twenty".