16544221 has 4 divisors (see below), whose sum is σ = 16552512. Its totient is φ = 16535932.

The previous prime is 16544219. The next prime is 16544261. The reversal of 16544221 is 12244561.

It is a happy number.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 16544221 - 2¹ = 16544219 is a prime.

It is a super-2 number, since 2×16544221² = 547422496993682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16544261) 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, 876 + ... + 5818.

It is an arithmetic number, because the mean of its divisors is an integer number (4138128).

Almost surely, 2^16544221 is an apocalyptic number.

It is an amenable number.

16544221 is a deficient number, since it is larger than the sum of its proper divisors (8291).

16544221 is an equidigital number, since it uses as much as digits as its factorization.

16544221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8290.

The product of its digits is 1920, while the sum is 25.

The square root of 16544221 is about 4067.4587889738. The cubic root of 16544221 is about 254.8093974881.

Adding to 16544221 its reverse (12244561), we get a palindrome (28788782).

The spelling of 16544221 in words is "sixteen million, five hundred forty-four thousand, two hundred twenty-one".