21121304121 has 24 divisors (see below), whose sum is σ = 32659105024. Its totient is φ = 13626642960.

The previous prime is 21121304093. The next prime is 21121304129. The reversal of 21121304121 is 12140312112.

It is not a de Polignac number, because 21121304121 - 2⁷ = 21121303993 is a prime.

It is a super-2 number, since 2×21121304121² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121304094 and 21121304103.

It is not an unprimeable number, because it can be changed into a prime (21121304129) 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 23 ways as a sum of consecutive naturals, for example, 1394386 + ... + 1409451.

Almost surely, 2^21121304121 is an apocalyptic number.

It is an amenable number.

21121304121 is a deficient number, since it is larger than the sum of its proper divisors (11537800903).

21121304121 is an equidigital number, since it uses as much as digits as its factorization.

21121304121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2803883 (or 2803871 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

Adding to 21121304121 its reverse (12140312112), we get a palindrome (33261616233).

The spelling of 21121304121 in words is "twenty-one billion, one hundred twenty-one million, three hundred four thousand, one hundred twenty-one".