821225 has 12 divisors (see below), whose sum is σ = 1031184. Its totient is φ = 648720.

The previous prime is 821209. The next prime is 821263. The reversal of 821225 is 522128.

It is not a de Polignac number, because 821225 - 2⁴ = 821209 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 821197 and 821206.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2522 + ... + 2828.

It is an arithmetic number, because the mean of its divisors is an integer number (85932).

2⁸²¹²²⁵ is an apocalyptic number.

It is an amenable number.

821225 is a deficient number, since it is larger than the sum of its proper divisors (209959).

821225 is a wasteful number, since it uses less digits than its factorization.

821225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 424 (or 419 counting only the distinct ones).

The product of its digits is 320, while the sum is 20.

The square root of 821225 is about 906.2146544831. The cubic root of 821225 is about 93.6456023070.

The spelling of 821225 in words is "eight hundred twenty-one thousand, two hundred twenty-five".