21122101220 has 144 divisors (see below), whose sum is σ = 49620438000. Its totient is φ = 7545753600.

The previous prime is 21122101211. The next prime is 21122101249. The reversal of 21122101220 is 2210122112.

It can be written as a sum of positive squares in 8 ways, for example, as 13498276 + 21108602944 = 3674^2 + 145288^2 .

It is a super-2 number, since 2×21122101220² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21122101195 and 21122101204.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 60521606 + ... + 60521954.

It is an arithmetic number, because the mean of its divisors is an integer number (344586375).

Almost surely, 2^21122101220 is an apocalyptic number.

21122101220 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 21122101220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24810219000).

21122101220 is an abundant number, since it is smaller than the sum of its proper divisors (28498336780).

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

21122101220 is a wasteful number, since it uses less digits than its factorization.

21122101220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 750 (or 737 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21122101220 its reverse (2210122112), we get a palindrome (23332223332).

The spelling of 21122101220 in words is "twenty-one billion, one hundred twenty-two million, one hundred one thousand, two hundred twenty".