3521221 has 6 divisors (see below), whose sum is σ = 3870566. Its totient is φ = 3201000.

The previous prime is 3521201. The next prime is 3521237. The reversal of 3521221 is 1221253.

It can be written as a sum of positive squares in only one way, i.e., 1920996 + 1600225 = 1386^2 + 1265^2 .

It is not a de Polignac number, because 3521221 - 2¹⁵ = 3488453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3521195 and 3521204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3521201) 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 5 ways as a sum of consecutive naturals, for example, 14430 + ... + 14671.

Almost surely, 2^3521221 is an apocalyptic number.

It is an amenable number.

3521221 is a deficient number, since it is larger than the sum of its proper divisors (349345).

3521221 is a wasteful number, since it uses less digits than its factorization.

3521221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29123 (or 29112 counting only the distinct ones).

The product of its digits is 120, while the sum is 16.

The square root of 3521221 is about 1876.4916733095. The cubic root of 3521221 is about 152.1356850523.

Adding to 3521221 its reverse (1221253), we get a palindrome (4742474).

Subtracting from 3521221 its reverse (1221253), we obtain a cube (2299968 = 132³).

The spelling of 3521221 in words is "three million, five hundred twenty-one thousand, two hundred twenty-one".