213864 has 64 divisors (see below), whose sum is σ = 652800. Its totient is φ = 57024.

The previous prime is 213859. The next prime is 213881. The reversal of 213864 is 468312.

It is a happy number.

213864 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nude number because it is divisible by every one of its digits.

It is one of the 548 Lynch-Bell numbers.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3159 + ... + 3225.

It is an arithmetic number, because the mean of its divisors is an integer number (10200).

2²¹³⁸⁶⁴ is an apocalyptic number.

213864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 213864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (326400).

213864 is an abundant number, since it is smaller than the sum of its proper divisors (438936).

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

213864 is a wasteful number, since it uses less digits than its factorization.

213864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102 (or 98 counting only the distinct ones).

The product of its digits is 1152, while the sum is 24.

The square root of 213864 is about 462.4543220687. The cubic root of 213864 is about 59.8015666827.

213864 divided by its sum of digits (24) gives a triangular number (8911 = T₁₃₃).

The spelling of 213864 in words is "two hundred thirteen thousand, eight hundred sixty-four".