256890 has 16 divisors (see below), whose sum is σ = 616608. Its totient is φ = 68496.

The previous prime is 256889. The next prime is 256901. The reversal of 256890 is 98652.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 8563 = 256890 / (2 + 5 + 6 + 8 + 9 + 0).

It is a Curzon number.

It is an unprimeable number.

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, 4252 + ... + 4311.

It is an arithmetic number, because the mean of its divisors is an integer number (38538).

2²⁵⁶⁸⁹⁰ is an apocalyptic number.

256890 is an abundant number, since it is smaller than the sum of its proper divisors (359718).

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

256890 is a wasteful number, since it uses less digits than its factorization.

256890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8573.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 256890 is about 506.8431710105. The cubic root of 256890 is about 63.5695396244.

The spelling of 256890 in words is "two hundred fifty-six thousand, eight hundred ninety".