821224 has 8 divisors (see below), whose sum is σ = 1539810. Its totient is φ = 410608.

The previous prime is 821209. The next prime is 821263. The reversal of 821224 is 422128.

821224 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 669124 + 152100 = 818^2 + 390^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a hoax number, since the sum of its digits (19) coincides with the sum of the digits of its distinct prime factors.

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

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51319 + ... + 51334.

2⁸²¹²²⁴ is an apocalyptic number.

It is an amenable number.

821224 is a deficient number, since it is larger than the sum of its proper divisors (718586).

821224 is a wasteful number, since it uses less digits than its factorization.

821224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102659 (or 102655 counting only the distinct ones).

The product of its digits is 256, while the sum is 19.

The square root of 821224 is about 906.2141027373. The cubic root of 821224 is about 93.6455642964.

The spelling of 821224 in words is "eight hundred twenty-one thousand, two hundred twenty-four".