21021120212121 has 48 divisors (see below), whose sum is σ = 31432802296896. Its totient is φ = 13528915964928.

The previous prime is 21021120212063. The next prime is 21021120212137. The reversal of 21021120212121 is 12121202112012.

21021120212121 is a `hidden beast` number, since 210 + 2 + 1 + 120 + 212 + 121 = 666.

It is not a de Polignac number, because 21021120212121 - 2¹⁴ = 21021120195737 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21021120212094 and 21021120212103.

It is not an unprimeable number, because it can be changed into a prime (21021120212021) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 17343901 + ... + 18516293.

It is an arithmetic number, because the mean of its divisors is an integer number (654850047852).

Almost surely, 2^{21021120212121} is an apocalyptic number.

It is an amenable number.

21021120212121 is a deficient number, since it is larger than the sum of its proper divisors (10411682084775).

21021120212121 is a wasteful number, since it uses less digits than its factorization.

21021120212121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1172982 (or 1172979 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21021120212121 its reverse (12121202112012), we get a palindrome (33142322324133).

The spelling of 21021120212121 in words is "twenty-one trillion, twenty-one billion, one hundred twenty million, two hundred twelve thousand, one hundred twenty-one".