21221021121021 has 8 divisors (see below), whose sum is σ = 31438549808960. Its totient is φ = 14147347413996.

The previous prime is 21221021120977. The next prime is 21221021121059. The reversal of 21221021121021 is 12012112012212.

21221021121021 is a `hidden beast` number, since 2 + 1 + 221 + 0 + 211 + 210 + 21 = 666.

It is not a de Polignac number, because 21221021121021 - 2²² = 21221016926717 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21221021120985 and 21221021121003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221021121121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 392981872585 + ... + 392981872638.

It is an arithmetic number, because the mean of its divisors is an integer number (3929818726120).

Almost surely, 2^{21221021121021} is an apocalyptic number.

It is an amenable number.

21221021121021 is a deficient number, since it is larger than the sum of its proper divisors (10217528687939).

21221021121021 is an equidigital number, since it uses as much as digits as its factorization.

21221021121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 785963745232 (or 785963745226 counting only the distinct ones).

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

Adding to 21221021121021 its reverse (12012112012212), we get a palindrome (33233133133233).

The spelling of 21221021121021 in words is "twenty-one trillion, two hundred twenty-one billion, twenty-one million, one hundred twenty-one thousand, twenty-one".