261310320 has 80 divisors (see below), whose sum is σ = 900076320. Its totient is φ = 69682176.

The previous prime is 261310229. The next prime is 261310321. The reversal of 261310320 is 23013162.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 261310293 and 261310302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261310321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 58329 + ... + 62648.

It is an arithmetic number, because the mean of its divisors is an integer number (11250954).

Almost surely, 2^261310320 is an apocalyptic number.

261310320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261310320 is an abundant number, since it is smaller than the sum of its proper divisors (638766000).

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

261310320 is a wasteful number, since it uses less digits than its factorization.

261310320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120999 (or 120987 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 261310320 is about 16165.0957312352. The cubic root of 261310320 is about 639.3208289947.

Adding to 261310320 its reverse (23013162), we get a palindrome (284323482).

The spelling of 261310320 in words is "two hundred sixty-one million, three hundred ten thousand, three hundred twenty".