256986 has 16 divisors (see below), whose sum is σ = 571200. Its totient is φ = 85644.

The previous prime is 256981. The next prime is 257003. The reversal of 256986 is 689652.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 256986.

It is not an unprimeable number, because it can be changed into a prime (256981) 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 7 ways as a sum of consecutive naturals, for example, 2326 + ... + 2433.

It is an arithmetic number, because the mean of its divisors is an integer number (35700).

2²⁵⁶⁹⁸⁶ is an apocalyptic number.

256986 is an abundant number, since it is smaller than the sum of its proper divisors (314214).

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

256986 is a wasteful number, since it uses less digits than its factorization.

256986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4770 (or 4764 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 256986 is about 506.9378660152. The cubic root of 256986 is about 63.5774573009.

The spelling of 256986 in words is "two hundred fifty-six thousand, nine hundred eighty-six".