6521221256 has 32 divisors (see below), whose sum is σ = 13769153280. Its totient is φ = 2868571200.

The previous prime is 6521221253. The next prime is 6521221297.

6521221256 is nontrivially palindromic in base 10.

It is not an unprimeable number, because it can be changed into a prime (6521221253) 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 7 ways as a sum of consecutive naturals, for example, 1192511 + ... + 1197966.

It is an arithmetic number, because the mean of its divisors is an integer number (430286040).

Almost surely, 2^6521221256 is an apocalyptic number.

It is an amenable number.

6521221256 is an abundant number, since it is smaller than the sum of its proper divisors (7247932024).

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

6521221256 is a wasteful number, since it uses less digits than its factorization.

6521221256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2390525 (or 2390521 counting only the distinct ones).

The product of its digits is 14400, while the sum is 32.

The square root of 6521221256 is about 80754.0788815029. The cubic root of 6521221256 is about 1868.2843612423.

It can be divided in two parts, 65212 and 21256, that added together give a palindrome (86468).

The spelling of 6521221256 in words is "six billion, five hundred twenty-one million, two hundred twenty-one thousand, two hundred fifty-six".