21221101220220 has 144 divisors (see below), whose sum is σ = 72568761420960. Its totient is φ = 5144509370880.

The previous prime is 21221101220191. The next prime is 21221101220233. The reversal of 21221101220220 is 2202210112212.

It is a happy number.

21221101220220 is a `hidden beast` number, since 2 + 1 + 221 + 1 + 0 + 1 + 220 + 220 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21221101220193 and 21221101220202.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 162324477 + ... + 162455156.

It is an arithmetic number, because the mean of its divisors is an integer number (503949732090).

Almost surely, 2^{21221101220220} is an apocalyptic number.

21221101220220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221101220220 is an abundant number, since it is smaller than the sum of its proper divisors (51347660200740).

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

21221101220220 is a wasteful number, since it uses less digits than its factorization.

21221101220220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324779673 (or 324779654 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21221101220220 its reverse (2202210112212), we get a palindrome (23423311332432).

The spelling of 21221101220220 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred one million, two hundred twenty thousand, two hundred twenty".