2561878509 has 8 divisors (see below), whose sum is σ = 3595619040. Its totient is φ = 1618028496.

The previous prime is 2561878507. The next prime is 2561878519. The reversal of 2561878509 is 9058781652.

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

It is not a de Polignac number, because 2561878509 - 2¹ = 2561878507 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2561878507) 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 7 ways as a sum of consecutive naturals, for example, 22472562 + ... + 22472675.

It is an arithmetic number, because the mean of its divisors is an integer number (449452380).

Almost surely, 2^2561878509 is an apocalyptic number.

It is an amenable number.

2561878509 is a deficient number, since it is larger than the sum of its proper divisors (1033740531).

2561878509 is a wasteful number, since it uses less digits than its factorization.

2561878509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44945259.

The product of its (nonzero) digits is 1209600, while the sum is 51.

The square root of 2561878509 is about 50615.0028054924. The cubic root of 2561878509 is about 1368.3152802401.

The spelling of 2561878509 in words is "two billion, five hundred sixty-one million, eight hundred seventy-eight thousand, five hundred nine".