1222821 has 12 divisors (see below), whose sum is σ = 1859520. Its totient is φ = 772200.

The previous prime is 1222811. The next prime is 1222829. The reversal of 1222821 is 1282221.

It is a happy number.

It is not a de Polignac number, because 1222821 - 2⁵ = 1222789 is a prime.

1222821 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1222794 and 1222803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1222829) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3405 + ... + 3746.

It is an arithmetic number, because the mean of its divisors is an integer number (154960).

2^1222821 is an apocalyptic number.

It is an amenable number.

1222821 is a deficient number, since it is larger than the sum of its proper divisors (636699).

1222821 is a wasteful number, since it uses less digits than its factorization.

1222821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7176 (or 7173 counting only the distinct ones).

The product of its digits is 128, while the sum is 18.

The square root of 1222821 is about 1105.8123710648. The cubic root of 1222821 is about 106.9352681519.

The spelling of 1222821 in words is "one million, two hundred twenty-two thousand, eight hundred twenty-one".