255840 has 96 divisors (see below), whose sum is σ = 889056. Its totient is φ = 61440.

The previous prime is 255839. The next prime is 255841. The reversal of 255840 is 48552.

It is an interprime number because it is at equal distance from previous prime (255839) and next prime (255841).

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 255840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (255841) 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, 6220 + ... + 6260.

It is an arithmetic number, because the mean of its divisors is an integer number (9261).

2²⁵⁵⁸⁴⁰ is an apocalyptic number.

255840 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 255840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (444528).

255840 is an abundant number, since it is smaller than the sum of its proper divisors (633216).

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

255840 is a wasteful number, since it uses less digits than its factorization.

255840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 24.

The square root of 255840 is about 505.8062870309. The cubic root of 255840 is about 63.4828109798.

The spelling of 255840 in words is "two hundred fifty-five thousand, eight hundred forty".