256643184 has 120 divisors (see below), whose sum is σ = 811971840. Its totient is φ = 69455232.

The previous prime is 256643183. The next prime is 256643207. The reversal of 256643184 is 481346652.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256643183) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 41817 + ... + 47559.

It is an arithmetic number, because the mean of its divisors is an integer number (6766432).

Almost surely, 2^256643184 is an apocalyptic number.

256643184 is a gapful number since it is divisible by the number (24) 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 256643184, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (405985920).

256643184 is an abundant number, since it is smaller than the sum of its proper divisors (555328656).

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

256643184 is a wasteful number, since it uses less digits than its factorization.

256643184 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5787 (or 5774 counting only the distinct ones).

The product of its digits is 138240, while the sum is 39.

The square root of 256643184 is about 16020.0868911501. The cubic root of 256643184 is about 635.4917421889.

The spelling of 256643184 in words is "two hundred fifty-six million, six hundred forty-three thousand, one hundred eighty-four".