213856 has 24 divisors (see below), whose sum is σ = 433944. Its totient is φ = 103680.

The previous prime is 213847. The next prime is 213859. The reversal of 213856 is 658312.

It is a happy number.

It is a Smith number, since the sum of its digits (25) 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 213856.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213859) by changing a digit.

213856 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1231 + ... + 1393.

It is an arithmetic number, because the mean of its divisors is an integer number (18081).

2²¹³⁸⁵⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 213856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (216972).

213856 is an abundant number, since it is smaller than the sum of its proper divisors (220088).

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

213856 is a wasteful number, since it uses less digits than its factorization.

213856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214 (or 206 counting only the distinct ones).

The product of its digits is 1440, while the sum is 25.

The square root of 213856 is about 462.4456724849. The cubic root of 213856 is about 59.8008210086.

Adding to 213856 its product of digits (1440), we get a square (215296 = 464²).

The spelling of 213856 in words is "two hundred thirteen thousand, eight hundred fifty-six".