Adding to 261520 its reverse (25162), we get a palindrome (286682).
It is a happy number.
It is a tau number, because it is divible by the number of its divisors (40).
It is a nialpdrome in base 8.
261520 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
2261520 is an apocalyptic number.
261520 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 261520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (348192).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
261520 is a wasteful number, since it uses less digits than its factorization.
261520 is an odious number, because the sum of its binary digits is odd.
The square root of 261520 is about 511.3902619331. The cubic root of 261520 is about 63.9491784039.
The spelling of 261520 in words is "two hundred sixty-one thousand, five hundred twenty".