256642 has 4 divisors (see below), whose sum is σ = 384966. Its totient is φ = 128320.

The previous prime is 256639. The next prime is 256643. The reversal of 256642 is 246652.

256642 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 231361 + 25281 = 481^2 + 159^2 .

It is not an unprimeable number, because it can be changed into a prime (256643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64159 + ... + 64162.

2²⁵⁶⁶⁴² is an apocalyptic number.

256642 is a deficient number, since it is larger than the sum of its proper divisors (128324).

256642 is a wasteful number, since it uses less digits than its factorization.

256642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128323.

The product of its digits is 2880, while the sum is 25.

The square root of 256642 is about 506.5984603214. The cubic root of 256642 is about 63.5490764926.

It can be divided in two parts, 256 and 642, that added together give a palindrome (898).

The spelling of 256642 in words is "two hundred fifty-six thousand, six hundred forty-two".