215864 has 24 divisors (see below), whose sum is σ = 446880. Its totient is φ = 97680.

The previous prime is 215863. The next prime is 215893. The reversal of 215864 is 468512.

215864 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

215864 is an esthetic number in base 6, because in such base its adjacent digits differ by 1.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 215864.

It is not an unprimeable number, because it can be changed into a prime (215863) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 857 + ... + 1079.

It is an arithmetic number, because the mean of its divisors is an integer number (18620).

2²¹⁵⁸⁶⁴ 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 215864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (223440).

215864 is an abundant number, since it is smaller than the sum of its proper divisors (231016).

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

215864 is a wasteful number, since it uses less digits than its factorization.

215864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251 (or 236 counting only the distinct ones).

The product of its digits is 1920, while the sum is 26.

The square root of 215864 is about 464.6116658027. The cubic root of 215864 is about 59.9874047636.

It can be divided in two parts, 2158 and 64, that added together give a palindrome (2222).

The spelling of 215864 in words is "two hundred fifteen thousand, eight hundred sixty-four".