256671 has 18 divisors (see below), whose sum is σ = 396240. Its totient is φ = 160056.

The previous prime is 256661. The next prime is 256687. The reversal of 256671 is 176652.

It is not a de Polignac number, because 256671 - 2⁵ = 256639 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 3210 + ... + 3288.

2²⁵⁶⁶⁷¹ is an apocalyptic number.

256671 is a deficient number, since it is larger than the sum of its proper divisors (139569).

256671 is a wasteful number, since it uses less digits than its factorization.

256671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123 (or 101 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 256671 is about 506.6270817870. The cubic root of 256671 is about 63.5514700393.

The spelling of 256671 in words is "two hundred fifty-six thousand, six hundred seventy-one".