261520560 has 240 divisors, whose sum is σ = 1056956160. Its totient is φ = 56609280.

The previous prime is 261520547. The next prime is 261520561. The reversal of 261520560 is 65025162.

It is a tau number, because it is divible by the number of its divisors (240).

It is not an unprimeable number, because it can be changed into a prime (261520561) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 94395 + ... + 97125.

It is an arithmetic number, because the mean of its divisors is an integer number (4403984).

Almost surely, 2^261520560 is an apocalyptic number.

261520560 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 261520560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (528478080).

261520560 is an abundant number, since it is smaller than the sum of its proper divisors (795435600).

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

261520560 is a wasteful number, since it uses less digits than its factorization.

261520560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2776 (or 2767 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 261520560 is about 16171.5973237031. The cubic root of 261520560 is about 639.4922404924.

The spelling of 261520560 in words is "two hundred sixty-one million, five hundred twenty thousand, five hundred sixty".