3506821 has 4 divisors (see below), whose sum is σ = 3541644. Its totient is φ = 3472000.

The previous prime is 3506819. The next prime is 3506863. The reversal of 3506821 is 1286053.

It is a happy number.

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 2842596 + 664225 = 1686^2 + 815^2 .

It is a cyclic number.

It is not a de Polignac number, because 3506821 - 2¹ = 3506819 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3506801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17260 + ... + 17461.

It is an arithmetic number, because the mean of its divisors is an integer number (885411).

Almost surely, 2^3506821 is an apocalyptic number.

It is an amenable number.

3506821 is a deficient number, since it is larger than the sum of its proper divisors (34823).

3506821 is a wasteful number, since it uses less digits than its factorization.

3506821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34822.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 3506821 is about 1872.6507949962. The cubic root of 3506821 is about 151.9280158921.

The spelling of 3506821 in words is "three million, five hundred six thousand, eight hundred twenty-one".