20121222210021 has 20 divisors (see below), whose sum is σ = 30058097908300. Its totient is φ = 13413938535936.

The previous prime is 20121222209971. The next prime is 20121222210029. The reversal of 20121222210021 is 12001222212102.

It is a happy number.

20121222210021 is a `hidden beast` number, since 201 + 212 + 22 + 210 + 0 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13864370333121 + 6256851876900 = 3723489^2 + 2501370^2 .

It is not a de Polignac number, because 20121222210021 - 2⁹ = 20121222209509 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20121222209976 and 20121222210003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121222210029) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3363975 + ... + 7180443.

It is an arithmetic number, because the mean of its divisors is an integer number (1502904895415).

Almost surely, 2^{20121222210021} is an apocalyptic number.

It is an amenable number.

20121222210021 is a deficient number, since it is larger than the sum of its proper divisors (9936875698279).

20121222210021 is an equidigital number, since it uses as much as digits as its factorization.

20121222210021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3881570 (or 3881561 counting only the distinct ones).

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

Adding to 20121222210021 its reverse (12001222212102), we get a palindrome (32122444422123).

The spelling of 20121222210021 in words is "twenty trillion, one hundred twenty-one billion, two hundred twenty-two million, two hundred ten thousand, twenty-one".