256721760 has 144 divisors (see below), whose sum is σ = 927684576. Its totient is φ = 64425984.

The previous prime is 256721747. The next prime is 256721789. The reversal of 256721760 is 67127652.

256721760 is a `hidden beast` number, since 2 + 567 + 21 + 76 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19237 + ... + 29723.

It is an arithmetic number, because the mean of its divisors is an integer number (6442254).

Almost surely, 2^256721760 is an apocalyptic number.

256721760 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 256721760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (463842288).

256721760 is an abundant number, since it is smaller than the sum of its proper divisors (670962816).

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

256721760 is a wasteful number, since it uses less digits than its factorization.

256721760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10525 (or 10514 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 36.

The square root of 256721760 is about 16022.5391246207. The cubic root of 256721760 is about 635.5565913738.

The spelling of 256721760 in words is "two hundred fifty-six million, seven hundred twenty-one thousand, seven hundred sixty".