12312121021 has 16 divisors (see below), whose sum is σ = 13193202240. Its totient is φ = 11449301760.

The previous prime is 12312121001. The next prime is 12312121027. The reversal of 12312121021 is 12012121321.

It is a cyclic number.

It is not a de Polignac number, because 12312121021 - 2¹³ = 12312112829 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12312120986 and 12312121004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12312121027) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 464866 + ... + 490636.

It is an arithmetic number, because the mean of its divisors is an integer number (824575140).

Almost surely, 2^12312121021 is an apocalyptic number.

It is an amenable number.

12312121021 is a deficient number, since it is larger than the sum of its proper divisors (881081219).

12312121021 is a wasteful number, since it uses less digits than its factorization.

12312121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26124.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 12312121021 its reverse (12012121321), we get a palindrome (24324242342).

The spelling of 12312121021 in words is "twelve billion, three hundred twelve million, one hundred twenty-one thousand, twenty-one".