21121110022221 has 48 divisors (see below), whose sum is σ = 34144142340672. Its totient is φ = 12473208403200.

The previous prime is 21121110022211. The next prime is 21121110022351. The reversal of 21121110022221 is 12222001112112.

21121110022221 is a `hidden beast` number, since 211 + 211 + 1 + 0 + 0 + 22 + 221 = 666.

It is not a de Polignac number, because 21121110022221 - 2²⁷ = 21120975804493 is a prime.

It is a super-2 number, since 2×21121110022221² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121110022194 and 21121110022203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121110022211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 17005750 + ... + 18205431.

It is an arithmetic number, because the mean of its divisors is an integer number (711336298764).

Almost surely, 2^{21121110022221} is an apocalyptic number.

It is an amenable number.

21121110022221 is a deficient number, since it is larger than the sum of its proper divisors (13023032318451).

21121110022221 is a wasteful number, since it uses less digits than its factorization.

21121110022221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35211354 (or 35211351 counting only the distinct ones).

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

Adding to 21121110022221 its reverse (12222001112112), we get a palindrome (33343111134333).

The spelling of 21121110022221 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred ten million, twenty-two thousand, two hundred twenty-one".