805221 has 10 divisors (see below), whose sum is σ = 1202982. Its totient is φ = 536760.

The previous prime is 805219. The next prime is 805223. The reversal of 805221 is 122508.

It is an interprime number because it is at equal distance from previous prime (805219) and next prime (805223).

It can be written as a sum of positive squares in only one way, i.e., 408321 + 396900 = 639^2 + 630^2 .

It is not a de Polignac number, because 805221 - 2¹ = 805219 is a prime.

It is an Ulam number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 805194 and 805203.

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 805221.

It is not an unprimeable number, because it can be changed into a prime (805223) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 4890 + ... + 5051.

2⁸⁰⁵²²¹ is an apocalyptic number.

805221 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

805221 is a deficient number, since it is larger than the sum of its proper divisors (397761).

805221 is an equidigital number, since it uses as much as digits as its factorization.

805221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9953 (or 9944 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 805221 is about 897.3410722797. The cubic root of 805221 is about 93.0332867318.

Adding to 805221 its reverse (122508), we get a palindrome (927729).

The spelling of 805221 in words is "eight hundred five thousand, two hundred twenty-one".