261855360 has 288 divisors, whose sum is σ = 982764900. Its totient is φ = 64217088.

The previous prime is 261855353. The next prime is 261855379. The reversal of 261855360 is 63558162.

261855360 is a `hidden beast` number, since 2 + 618 + 5 + 5 + 36 + 0 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 968256 + 260887104 = 984^2 + 16152^2 .

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable 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 35 ways as a sum of consecutive naturals, for example, 973306 + ... + 973574.

Almost surely, 2^261855360 is an apocalyptic number.

261855360 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261855360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (491382450).

261855360 is an abundant number, since it is smaller than the sum of its proper divisors (720909540).

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

261855360 is a wasteful number, since it uses less digits than its factorization.

261855360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320 (or 292 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The square root of 261855360 is about 16181.9454949026. The cubic root of 261855360 is about 639.7650179013.

The spelling of 261855360 in words is "two hundred sixty-one million, eight hundred fifty-five thousand, three hundred sixty".