2556403321 has 4 divisors (see below), whose sum is σ = 2558879092. Its totient is φ = 2553927552.

The previous prime is 2556403303. The next prime is 2556403391. The reversal of 2556403321 is 1233046552.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2090318400 + 466084921 = 45720^2 + 21589^2 .

It is a cyclic number.

It is not a de Polignac number, because 2556403321 - 2¹¹ = 2556401273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2556403391) 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 3 ways as a sum of consecutive naturals, for example, 1236336 + ... + 1238401.

It is an arithmetic number, because the mean of its divisors is an integer number (639719773).

Almost surely, 2^2556403321 is an apocalyptic number.

It is an amenable number.

2556403321 is a deficient number, since it is larger than the sum of its proper divisors (2475771).

2556403321 is a wasteful number, since it uses less digits than its factorization.

2556403321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2475770.

The product of its (nonzero) digits is 21600, while the sum is 31.

The square root of 2556403321 is about 50560.8872647623. The cubic root of 2556403321 is about 1367.3398076444.

Adding to 2556403321 its reverse (1233046552), we get a palindrome (3789449873).

The spelling of 2556403321 in words is "two billion, five hundred fifty-six million, four hundred three thousand, three hundred twenty-one".