261278586 has 24 divisors (see below), whose sum is σ = 566429760. Its totient is φ = 87042696.

The previous prime is 261278581. The next prime is 261278669. The reversal of 261278586 is 685872162.

261278586 is a `hidden beast` number, since 2 + 61 + 2 + 7 + 8 + 586 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (261278581) 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 11 ways as a sum of consecutive naturals, for example, 41311 + ... + 47213.

It is an arithmetic number, because the mean of its divisors is an integer number (23601240).

Almost surely, 2^261278586 is an apocalyptic number.

261278586 is an abundant number, since it is smaller than the sum of its proper divisors (305151174).

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

261278586 is a wasteful number, since it uses less digits than its factorization.

261278586 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8370 (or 8367 counting only the distinct ones).

The product of its digits is 322560, while the sum is 45.

The square root of 261278586 is about 16164.1141421360. The cubic root of 261278586 is about 639.2949478526.

The spelling of 261278586 in words is "two hundred sixty-one million, two hundred seventy-eight thousand, five hundred eighty-six".