261860 has 12 divisors (see below), whose sum is σ = 549948. Its totient is φ = 104736.

The previous prime is 261847. The next prime is 261881. The reversal of 261860 is 68162.

It can be written as a sum of positive squares in 2 ways, for example, as 173056 + 88804 = 416^2 + 298^2 .

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

261860 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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, 6527 + ... + 6566.

It is an arithmetic number, because the mean of its divisors is an integer number (45829).

2²⁶¹⁸⁶⁰ is an apocalyptic number.

261860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261860 is an abundant number, since it is smaller than the sum of its proper divisors (288088).

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

261860 is a wasteful number, since it uses less digits than its factorization.

261860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13102 (or 13100 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 261860 is about 511.7225810925. The cubic root of 261860 is about 63.9768796695.

It can be divided in two parts, 2618 and 60, that multiplied together give a triangular number (157080 = T₅₆₀).

The spelling of 261860 in words is "two hundred sixty-one thousand, eight hundred sixty".