21022001220 has 96 divisors (see below), whose sum is σ = 64239106176. Its totient is φ = 5094144000.

The previous prime is 21022001191. The next prime is 21022001227. The reversal of 21022001220 is 2210022012.

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 = 21022001196 and 21022001205.

It is not an unprimeable number, because it can be changed into a prime (21022001227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2118270 + ... + 2128170.

It is an arithmetic number, because the mean of its divisors is an integer number (669157356).

Almost surely, 2^21022001220 is an apocalyptic number.

21022001220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21022001220 is an abundant number, since it is smaller than the sum of its proper divisors (43217104956).

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

21022001220 is a wasteful number, since it uses less digits than its factorization.

21022001220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13141 (or 13139 counting only the distinct ones).

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

Adding to 21022001220 its reverse (2210022012), we get a palindrome (23232023232).

The spelling of 21022001220 in words is "twenty-one billion, twenty-two million, one thousand, two hundred twenty".