3521621 has 4 divisors (see below), whose sum is σ = 3527712. Its totient is φ = 3515532.

The previous prime is 3521561. The next prime is 3521627. The reversal of 3521621 is 1261253.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1261253 = 7 ⋅180179.

It is a cyclic number.

It is not a de Polignac number, because 3521621 - 2¹⁰ = 3520597 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3521593 and 3521602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3521627) 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, 2075 + ... + 3368.

It is an arithmetic number, because the mean of its divisors is an integer number (881928).

Almost surely, 2^3521621 is an apocalyptic number.

It is an amenable number.

3521621 is a deficient number, since it is larger than the sum of its proper divisors (6091).

3521621 is an equidigital number, since it uses as much as digits as its factorization.

3521621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6090.

The product of its digits is 360, while the sum is 20.

The square root of 3521621 is about 1876.5982521573. The cubic root of 3521621 is about 152.1414455513.

Adding to 3521621 its reverse (1261253), we get a palindrome (4782874).

The spelling of 3521621 in words is "three million, five hundred twenty-one thousand, six hundred twenty-one".