256740 has 48 divisors (see below), whose sum is σ = 786240. Its totient is φ = 62080.

The previous prime is 256723. The next prime is 256757. The reversal of 256740 is 47652.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (256723) and next prime (256757).

It is a nialpdrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 256740.

It is an unprimeable number.

256740 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 466 + ... + 854.

It is an arithmetic number, because the mean of its divisors is an integer number (16380).

2²⁵⁶⁷⁴⁰ is an apocalyptic number.

256740 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 256740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (393120).

256740 is an abundant number, since it is smaller than the sum of its proper divisors (529500).

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

256740 is a wasteful number, since it uses less digits than its factorization.

256740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412 (or 410 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 256740 is about 506.6951746366. The cubic root of 256740 is about 63.5571643049.

The spelling of 256740 in words is "two hundred fifty-six thousand, seven hundred forty".