261320 has 32 divisors (see below), whose sum is σ = 604800. Its totient is φ = 101568.

The previous prime is 261301. The next prime is 261323. The reversal of 261320 is 23162.

It is a nialpdrome in base 8.

It is a junction number, because it is equal to n+sod(n) for n = 261295 and 261304.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261323) by changing a digit.

261320 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 7 ways as a sum of consecutive naturals, for example, 1811 + ... + 1949.

It is an arithmetic number, because the mean of its divisors is an integer number (18900).

2²⁶¹³²⁰ is an apocalyptic number.

261320 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 261320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (302400).

261320 is an abundant number, since it is smaller than the sum of its proper divisors (343480).

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

261320 is a wasteful number, since it uses less digits than its factorization.

261320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197 (or 193 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 261320 is about 511.1946791585. The cubic root of 261320 is about 63.9328723247.

Adding to 261320 its reverse (23162), we get a palindrome (284482).

The spelling of 261320 in words is "two hundred sixty-one thousand, three hundred twenty".