2123121312 has 216 divisors, whose sum is σ = 6601182588. Its totient is φ = 646963200.

The previous prime is 2123121311. The next prime is 2123121331. The reversal of 2123121312 is 2131213212.

It can be written as a sum of positive squares in 6 ways, for example, as 73205136 + 2049916176 = 8556^2 + 45276^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2123121311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 8809512 + ... + 8809752.

Almost surely, 2^2123121312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2123121312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3300591294).

2123121312 is an abundant number, since it is smaller than the sum of its proper divisors (4478061276).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2123121312 is a wasteful number, since it uses less digits than its factorization.

2123121312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 464 (or 440 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 2123121312 is about 46077.3405482565. The cubic root of 2123121312 is about 1285.2618102202.

Adding to 2123121312 its reverse (2131213212), we get a palindrome (4254334524).

The spelling of 2123121312 in words is "two billion, one hundred twenty-three million, one hundred twenty-one thousand, three hundred twelve".