21202001220 has 192 divisors, whose sum is σ = 63823044096. Its totient is φ = 5245194240.

The previous prime is 21202001207. The next prime is 21202001263. The reversal of 21202001220 is 2210020212.

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 = 21202001196 and 21202001205.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 26601862 + ... + 26602658.

It is an arithmetic number, because the mean of its divisors is an integer number (332411688).

Almost surely, 2^21202001220 is an apocalyptic number.

21202001220 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 21202001220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31911522048).

21202001220 is an abundant number, since it is smaller than the sum of its proper divisors (42621042876).

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

21202001220 is a wasteful number, since it uses less digits than its factorization.

21202001220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1390 (or 1388 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 21202001220 its reverse (2210020212), we get a palindrome (23412021432).

The spelling of 21202001220 in words is "twenty-one billion, two hundred two million, one thousand, two hundred twenty".