3566821 has 4 divisors (see below), whose sum is σ = 3776652. Its totient is φ = 3356992.

The previous prime is 3566819. The next prime is 3566831. The reversal of 3566821 is 1286653.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3330625 + 236196 = 1825^2 + 486^2 .

It is a cyclic number.

It is not a de Polignac number, because 3566821 - 2¹ = 3566819 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3566831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104890 + ... + 104923.

It is an arithmetic number, because the mean of its divisors is an integer number (944163).

Almost surely, 2^3566821 is an apocalyptic number.

It is an amenable number.

3566821 is a deficient number, since it is larger than the sum of its proper divisors (209831).

3566821 is a wasteful number, since it uses less digits than its factorization.

3566821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 209830.

The product of its digits is 8640, while the sum is 31.

The square root of 3566821 is about 1888.6029227977. The cubic root of 3566821 is about 152.7895921614.

The spelling of 3566821 in words is "three million, five hundred sixty-six thousand, eight hundred twenty-one".