2556218209 has 8 divisors (see below), whose sum is σ = 2713340808. Its totient is φ = 2399846400.

The previous prime is 2556218173. The next prime is 2556218227. The reversal of 2556218209 is 9028126552.

It can be written as a sum of positive squares in 4 ways, for example, as 2169230625 + 386987584 = 46575^2 + 19672^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2556218209 - 2⁷ = 2556218081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2556218239) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 180672 + ... + 194305.

It is an arithmetic number, because the mean of its divisors is an integer number (339167601).

Almost surely, 2^2556218209 is an apocalyptic number.

It is an amenable number.

2556218209 is a deficient number, since it is larger than the sum of its proper divisors (157122599).

2556218209 is a wasteful number, since it uses less digits than its factorization.

2556218209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375395.

The product of its (nonzero) digits is 86400, while the sum is 40.

The square root of 2556218209 is about 50559.0566466583. The cubic root of 2556218209 is about 1367.3068033170.

The spelling of 2556218209 in words is "two billion, five hundred fifty-six million, two hundred eighteen thousand, two hundred nine".