261578 has 8 divisors (see below), whose sum is σ = 405120. Its totient is φ = 126540.

The previous prime is 261577. The next prime is 261581. The reversal of 261578 is 875162.

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

It is a self number, because there is not a number n which added to its sum of digits gives 261578.

It is not an unprimeable number, because it can be changed into a prime (261577) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2048 + ... + 2171.

It is an arithmetic number, because the mean of its divisors is an integer number (50640).

2²⁶¹⁵⁷⁸ is an apocalyptic number.

261578 is a deficient number, since it is larger than the sum of its proper divisors (143542).

261578 is a wasteful number, since it uses less digits than its factorization.

261578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4252.

The product of its digits is 3360, while the sum is 29.

The square root of 261578 is about 511.4469669477. The cubic root of 261578 is about 63.9539056117.

The spelling of 261578 in words is "two hundred sixty-one thousand, five hundred seventy-eight".