16642221 has 8 divisors (see below), whose sum is σ = 22208640. Its totient is φ = 11085312.

The previous prime is 16642217. The next prime is 16642231. The reversal of 16642221 is 12224661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 16642221 - 2² = 16642217 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 16642191 and 16642200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16642211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4845 + ... + 7533.

It is an arithmetic number, because the mean of its divisors is an integer number (2776080).

Almost surely, 2^16642221 is an apocalyptic number.

It is an amenable number.

16642221 is a deficient number, since it is larger than the sum of its proper divisors (5566419).

16642221 is a wasteful number, since it uses less digits than its factorization.

16642221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4755.

The product of its digits is 1152, while the sum is 24.

The square root of 16642221 is about 4079.4878355009. The cubic root of 16642221 is about 255.3115300565.

Adding to 16642221 its reverse (12224661), we get a palindrome (28866882).

The spelling of 16642221 in words is "sixteen million, six hundred forty-two thousand, two hundred twenty-one".