255581640 has 96 divisors (see below), whose sum is σ = 859318200. Its totient is φ = 65802240.

The previous prime is 255581549. The next prime is 255581647. The reversal of 255581640 is 46185552.

255581640 is a `hidden beast` number, since 2 + 5 + 5 + 5 + 8 + 1 + 640 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 125484804 + 130096836 = 11202^2 + 11406^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 255581595 and 255581604.

It is not an unprimeable number, because it can be changed into a prime (255581647) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1801 + ... + 22680.

Almost surely, 2^255581640 is an apocalyptic number.

255581640 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 255581640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (429659100).

255581640 is an abundant number, since it is smaller than the sum of its proper divisors (603736560).

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

255581640 is a wasteful number, since it uses less digits than its factorization.

255581640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24527 (or 24520 counting only the distinct ones).

The product of its (nonzero) digits is 48000, while the sum is 36.

The square root of 255581640 is about 15986.9209042892. The cubic root of 255581640 is about 634.6143441220.

The spelling of 255581640 in words is "two hundred fifty-five million, five hundred eighty-one thousand, six hundred forty".