21021220120122 has 24 divisors (see below), whose sum is σ = 45546255742260. Its totient is φ = 7007030478720.

The previous prime is 21021220120097. The next prime is 21021220120139. The reversal of 21021220120122 is 22102102212012.

It is a happy number.

21021220120122 is a `hidden beast` number, since 210 + 212 + 2 + 0 + 120 + 122 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 19610823984921 + 1410396135201 = 4428411^2 + 1187601^2 .

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 = 21021220120095 and 21021220120104.

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 11 ways as a sum of consecutive naturals, for example, 480079 + ... + 6501762.

Almost surely, 2^{21021220120122} is an apocalyptic number.

21021220120122 is an abundant number, since it is smaller than the sum of its proper divisors (24525035622138).

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

21021220120122 is a wasteful number, since it uses less digits than its factorization.

21021220120122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7149118 (or 7149115 counting only the distinct ones).

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

Adding to 21021220120122 its reverse (22102102212012), we get a palindrome (43123322332134).

The spelling of 21021220120122 in words is "twenty-one trillion, twenty-one billion, two hundred twenty million, one hundred twenty thousand, one hundred twenty-two".