810221 has 4 divisors (see below), whose sum is σ = 845472. Its totient is φ = 774972.

The previous prime is 810209. The next prime is 810223. The reversal of 810221 is 122018.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-810221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 810196 and 810205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (810223) 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, 17591 + ... + 17636.

It is an arithmetic number, because the mean of its divisors is an integer number (211368).

2⁸¹⁰²²¹ is an apocalyptic number.

It is an amenable number.

810221 is a deficient number, since it is larger than the sum of its proper divisors (35251).

810221 is a wasteful number, since it uses less digits than its factorization.

810221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35250.

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 810221 is about 900.1227694043. The cubic root of 810221 is about 93.2254521655.

Adding to 810221 its reverse (122018), we get a palindrome (932239).

The spelling of 810221 in words is "eight hundred ten thousand, two hundred twenty-one".