2556321001 has 4 divisors (see below), whose sum is σ = 2752961092. Its totient is φ = 2359680912.

The previous prime is 2556320989. The next prime is 2556321011. The reversal of 2556321001 is 1001236552.

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 1260321001 + 1296000000 = 35501^2 + 36000^2 .

It is a cyclic number.

It is not a de Polignac number, because 2556321001 - 2⁷ = 2556320873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2556321011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98320026 + ... + 98320051.

It is an arithmetic number, because the mean of its divisors is an integer number (688240273).

Almost surely, 2^2556321001 is an apocalyptic number.

It is an amenable number.

2556321001 is a deficient number, since it is larger than the sum of its proper divisors (196640091).

2556321001 is a wasteful number, since it uses less digits than its factorization.

2556321001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196640090.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 2556321001 is about 50560.0731902160. The cubic root of 2556321001 is about 1367.3251306931.

Adding to 2556321001 its reverse (1001236552), we get a palindrome (3557557553).

It can be divided in two parts, 25563 and 21001, that added together give a palindrome (46564).

The spelling of 2556321001 in words is "two billion, five hundred fifty-six million, three hundred twenty-one thousand, one".