21221113220 has 12 divisors (see below), whose sum is σ = 44564337804. Its totient is φ = 8488445280.

The previous prime is 21221113189. The next prime is 21221113241. The reversal of 21221113220 is 2231112212.

It can be written as a sum of positive squares in 2 ways, for example, as 12770356036 + 8450757184 = 113006^2 + 91928^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 530527811 + ... + 530527850.

It is an arithmetic number, because the mean of its divisors is an integer number (3713694817).

Almost surely, 2^21221113220 is an apocalyptic number.

21221113220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221113220 is an abundant number, since it is smaller than the sum of its proper divisors (23343224584).

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

21221113220 is a wasteful number, since it uses less digits than its factorization.

21221113220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1061055670 (or 1061055668 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21221113220 its reverse (2231112212), we get a palindrome (23452225432).

The spelling of 21221113220 in words is "twenty-one billion, two hundred twenty-one million, one hundred thirteen thousand, two hundred twenty".