261005824 has 60 divisors (see below), whose sum is σ = 534061242. Its totient is φ = 127426560.

The previous prime is 261005821. The next prime is 261005837. The reversal of 261005824 is 428500162.

It can be written as a sum of positive squares in 3 ways, for example, as 87609600 + 173396224 = 9360^2 + 13168^2 .

It is a junction number, because it is equal to n+sod(n) for n = 261005792 and 261005801.

It is not an unprimeable number, because it can be changed into a prime (261005821) 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 5 ways as a sum of consecutive naturals, for example, 1905084 + ... + 1905220.

Almost surely, 2^261005824 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261005824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (267030621).

261005824 is an abundant number, since it is smaller than the sum of its proper divisors (273055418).

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

261005824 is an frugal number, since it uses more digits than its factorization.

261005824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277 (or 200 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 261005824 is about 16155.6746686729. The cubic root of 261005824 is about 639.0724062273.

Adding to 261005824 its reverse (428500162), we get a palindrome (689505986).

The spelling of 261005824 in words is "two hundred sixty-one million, five thousand, eight hundred twenty-four".