261043560 has 320 divisors, whose sum is σ = 953441280. Its totient is φ = 63866880.

The previous prime is 261043511. The next prime is 261043579. The reversal of 261043560 is 65340162.

261043560 is a `hidden beast` number, since 2 + 61 + 0 + 43 + 560 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 2310064 + ... + 2310176.

It is an arithmetic number, because the mean of its divisors is an integer number (2979504).

Almost surely, 2^261043560 is an apocalyptic number.

261043560 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 261043560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (476720640).

261043560 is an abundant number, since it is smaller than the sum of its proper divisors (692397720).

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

261043560 is a wasteful number, since it uses less digits than its factorization.

261043560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190 (or 177 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 261043560 is about 16156.8425133131. The cubic root of 261043560 is about 639.1032035914.

The spelling of 261043560 in words is "two hundred sixty-one million, forty-three thousand, five hundred sixty".