261505160 has 96 divisors (see below), whose sum is σ = 691749720. Its totient is φ = 88704000.

The previous prime is 261505129. The next prime is 261505163. The reversal of 261505160 is 61505162.

It can be written as a sum of positive squares in 4 ways, for example, as 259660996 + 1844164 = 16114^2 + 1358^2 .

It is not an unprimeable number, because it can be changed into a prime (261505163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 197300 + ... + 198620.

Almost surely, 2^261505160 is an apocalyptic number.

261505160 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 261505160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (345874860).

261505160 is an abundant number, since it is smaller than the sum of its proper divisors (430244560).

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

261505160 is a wasteful number, since it uses less digits than its factorization.

261505160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1447 (or 1436 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 261505160 is about 16171.1211732520. The cubic root of 261505160 is about 639.4796877842.

The spelling of 261505160 in words is "two hundred sixty-one million, five hundred five thousand, one hundred sixty".