256993 has 8 divisors (see below), whose sum is σ = 285696. Its totient is φ = 229200.

The previous prime is 256981. The next prime is 257003. The reversal of 256993 is 399652.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 256993 - 2¹⁷ = 125921 is a prime.

It is a Duffinian number.

256993 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (256903) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 480 + ... + 862.

It is an arithmetic number, because the mean of its divisors is an integer number (35712).

2²⁵⁶⁹⁹³ is an apocalyptic number.

It is an amenable number.

256993 is a deficient number, since it is larger than the sum of its proper divisors (28703).

256993 is a wasteful number, since it uses less digits than its factorization.

256993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 455.

The product of its digits is 14580, while the sum is 34.

The square root of 256993 is about 506.9447701673. The cubic root of 256993 is about 63.5780345544.

It can be divided in two parts, 2569 and 93, that added together give a palindrome (2662).

The spelling of 256993 in words is "two hundred fifty-six thousand, nine hundred ninety-three".