3220821 has 12 divisors (see below), whose sum is σ = 4705740. Its totient is φ = 2122560.

The previous prime is 3220817. The next prime is 3220831. The reversal of 3220821 is 1280223.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 378225 + 2842596 = 615^2 + 1686^2 .

It is not a de Polignac number, because 3220821 - 2² = 3220817 is a prime.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 3220794 and 3220803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3220801) 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, 1210 + ... + 2811.

It is an arithmetic number, because the mean of its divisors is an integer number (392145).

Almost surely, 2^3220821 is an apocalyptic number.

It is an amenable number.

3220821 is a deficient number, since it is larger than the sum of its proper divisors (1484919).

3220821 is a wasteful number, since it uses less digits than its factorization.

3220821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4116 (or 4113 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 3220821 is about 1794.6645926189. The cubic root of 3220821 is about 147.6801743463.

The spelling of 3220821 in words is "three million, two hundred twenty thousand, eight hundred twenty-one".