261328320 has 336 divisors, whose sum is σ = 1002804192. Its totient is φ = 61931520.

The previous prime is 261328303. The next prime is 261328339. The reversal of 261328320 is 23823162.

261328320 is a `hidden beast` number, since 2 + 613 + 28 + 3 + 20 = 666.

261328320 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2312584 + ... + 2312696.

Almost surely, 2^261328320 is an apocalyptic number.

261328320 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 261328320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (501402096).

261328320 is an abundant number, since it is smaller than the sum of its proper divisors (741475872).

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

261328320 is a wasteful number, since it uses less digits than its factorization.

261328320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220 (or 207 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 261328320 is about 16165.6524767793. The cubic root of 261328320 is about 639.3355082347.

The spelling of 261328320 in words is "two hundred sixty-one million, three hundred twenty-eight thousand, three hundred twenty".