215823 has 4 divisors (see below), whose sum is σ = 287768. Its totient is φ = 143880.

The previous prime is 215801. The next prime is 215827. The reversal of 215823 is 328512.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 215823 - 2¹² = 211727 is a prime.

It is a d-powerful number, because it can be written as 2¹⁶ + 1 + 8² + 5⁷ + 2¹⁶ + 3⁸ .

It is a D-number.

It is a Duffinian number.

215823 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 215823.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215827) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35968 + ... + 35973.

It is an arithmetic number, because the mean of its divisors is an integer number (71942).

2²¹⁵⁸²³ is an apocalyptic number.

215823 is a deficient number, since it is larger than the sum of its proper divisors (71945).

215823 is an equidigital number, since it uses as much as digits as its factorization.

215823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71944.

The product of its digits is 480, while the sum is 21.

The square root of 215823 is about 464.5675408377. The cubic root of 215823 is about 59.9836066325.

It can be divided in two parts, 21582 and 3, that multiplied together give a palindrome (64746).

The spelling of 215823 in words is "two hundred fifteen thousand, eight hundred twenty-three".