21121002122220 has 960 divisors, whose sum is σ = 89279451942912. Its totient is φ = 4036677120000.

The previous prime is 21121002122189. The next prime is 21121002122249. The reversal of 21121002122220 is 2222120012112.

It is a happy number.

21121002122220 is a `hidden beast` number, since 21 + 1 + 210 + 0 + 212 + 2 + 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 = 21121002122193 and 21121002122202.

It is an unprimeable number.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 455652045 + ... + 455698395.

Almost surely, 2^{21121002122220} is an apocalyptic number.

21121002122220 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 21121002122220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44639725971456).

21121002122220 is an abundant number, since it is smaller than the sum of its proper divisors (68158449820692).

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

21121002122220 is a wasteful number, since it uses less digits than its factorization.

21121002122220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46684 (or 46673 counting only the distinct ones).

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

Adding to 21121002122220 its reverse (2222120012112), we get a palindrome (23343122134332).

The spelling of 21121002122220 in words is "twenty-one trillion, one hundred twenty-one billion, two million, one hundred twenty-two thousand, two hundred twenty".