16143221 has 4 divisors (see below), whose sum is σ = 16166700. Its totient is φ = 16119744.

The previous prime is 16143191. The next prime is 16143247. The reversal of 16143221 is 12234161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12234161 = 37 ⋅330653.

It can be written as a sum of positive squares in 2 ways, for example, as 972196 + 15171025 = 986^2 + 3895^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16143221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16143193 and 16143202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16143271) 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, 10676 + ... + 12093.

It is an arithmetic number, because the mean of its divisors is an integer number (4041675).

Almost surely, 2^16143221 is an apocalyptic number.

It is an amenable number.

16143221 is a deficient number, since it is larger than the sum of its proper divisors (23479).

16143221 is an equidigital number, since it uses as much as digits as its factorization.

16143221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23478.

The product of its digits is 288, while the sum is 20.

The square root of 16143221 is about 4017.8627403136. The cubic root of 16143221 is about 252.7338408180.

Adding to 16143221 its reverse (12234161), we get a palindrome (28377382).

The spelling of 16143221 in words is "sixteen million, one hundred forty-three thousand, two hundred twenty-one".