12121011221 has 16 divisors (see below), whose sum is σ = 13923873600. Its totient is φ = 10435392000.

The previous prime is 12121011173. The next prime is 12121011223. The reversal of 12121011221 is 12211012121.

It is not a de Polignac number, because 12121011221 - 2¹⁰ = 12121010197 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12121011196 and 12121011205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12121011223) 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 15 ways as a sum of consecutive naturals, for example, 681125 + ... + 698693.

It is an arithmetic number, because the mean of its divisors is an integer number (870242100).

Almost surely, 2^12121011221 is an apocalyptic number.

12121011221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12121011221 is a deficient number, since it is larger than the sum of its proper divisors (1802862379).

12121011221 is a wasteful number, since it uses less digits than its factorization.

12121011221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20900.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 12121011221 its reverse (12211012121), we get a palindrome (24332023342).

The spelling of 12121011221 in words is "twelve billion, one hundred twenty-one million, eleven thousand, two hundred twenty-one".