261304320 has 104 divisors (see below), whose sum is σ = 836268336. Its totient is φ = 69664768.

The previous prime is 261304279. The next prime is 261304339. The reversal of 261304320 is 23403162.

It is a happy number.

It is a nialpdrome in base 16.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59314 + ... + 63566.

Almost surely, 2^261304320 is an apocalyptic number.

261304320 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 261304320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (418134168).

261304320 is an abundant number, since it is smaller than the sum of its proper divisors (574964016).

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

261304320 is an equidigital number, since it uses as much as digits as its factorization.

261304320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4285 (or 4263 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 261304320 is about 16164.9101451261. The cubic root of 261304320 is about 639.3159357649.

Adding to 261304320 its reverse (23403162), we get a palindrome (284707482).

The spelling of 261304320 in words is "two hundred sixty-one million, three hundred four thousand, three hundred twenty".