2121305256 has 144 divisors (see below), whose sum is σ = 6793443540. Its totient is φ = 596090880.

The previous prime is 2121305227. The next prime is 2121305287. The reversal of 2121305256 is 6525031212.

It is a happy number.

2121305256 is a `hidden beast` number, since 2 + 1 + 2 + 130 + 525 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1846077156 + 275228100 = 42966^2 + 16590^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 210280 + ... + 220136.

Almost surely, 2^2121305256 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 2121305256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3396721770).

2121305256 is an abundant number, since it is smaller than the sum of its proper divisors (4672138284).

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

2121305256 is a wasteful number, since it uses less digits than its factorization.

2121305256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9944 (or 9930 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 2121305256 is about 46057.6297262462. The cubic root of 2121305256 is about 1284.8952472053.

Adding to 2121305256 its reverse (6525031212), we get a palindrome (8646336468).

The spelling of 2121305256 in words is "two billion, one hundred twenty-one million, three hundred five thousand, two hundred fifty-six".