256288720 has 80 divisors (see below), whose sum is σ = 633709440. Its totient is φ = 96118272.

The previous prime is 256288709. The next prime is 256288723. The reversal of 256288720 is 27882652.

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 (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256288723) 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, 155742 + ... + 157378.

It is an arithmetic number, because the mean of its divisors is an integer number (7921368).

Almost surely, 2^256288720 is an apocalyptic number.

256288720 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 256288720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (316854720).

256288720 is an abundant number, since it is smaller than the sum of its proper divisors (377420720).

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

256288720 is a wasteful number, since it uses less digits than its factorization.

256288720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1772 (or 1766 counting only the distinct ones).

The product of its (nonzero) digits is 107520, while the sum is 40.

The square root of 256288720 is about 16009.0199575115. The cubic root of 256288720 is about 635.1990365383.

The spelling of 256288720 in words is "two hundred fifty-six million, two hundred eighty-eight thousand, seven hundred twenty".