261206560 has 48 divisors (see below), whose sum is σ = 619882200. Its totient is φ = 104011776.

The previous prime is 261206549. The next prime is 261206563. The reversal of 261206560 is 65602162.

It can be written as a sum of positive squares in 4 ways, for example, as 256384144 + 4822416 = 16012^2 + 2196^2 .

It is not an unprimeable number, because it can be changed into a prime (261206563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33076 + ... + 40204.

Almost surely, 2^261206560 is an apocalyptic number.

261206560 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 261206560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (309941100).

261206560 is an abundant number, since it is smaller than the sum of its proper divisors (358675640).

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

261206560 is a wasteful number, since it uses less digits than its factorization.

261206560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7373 (or 7365 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 261206560 is about 16161.8860285550. The cubic root of 261206560 is about 639.2361981857.

The spelling of 261206560 in words is "two hundred sixty-one million, two hundred six thousand, five hundred sixty".