864220 has 24 divisors (see below), whose sum is σ = 2074464. Its totient is φ = 296256.

The previous prime is 864211. The next prime is 864221. The reversal of 864220 is 22468.

It is an Ulam number.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 864191 and 864200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (864221) by changing a digit.

864220 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 (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2947 + ... + 3226.

It is an arithmetic number, because the mean of its divisors is an integer number (86436).

2⁸⁶⁴²²⁰ is an apocalyptic number.

It is an amenable number.

864220 is an abundant number, since it is smaller than the sum of its proper divisors (1210244).

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

864220 is a wasteful number, since it uses less digits than its factorization.

864220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6189 (or 6187 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 864220 is about 929.6343367152. The cubic root of 864220 is about 95.2521464189.

Adding to 864220 its reverse (22468), we get a palindrome (886688).

The spelling of 864220 in words is "eight hundred sixty-four thousand, two hundred twenty".