16601221 has 8 divisors (see below), whose sum is σ = 20432384. Its totient is φ = 13134960.

The previous prime is 16601209. The next prime is 16601227. The reversal of 16601221 is 12210661.

16601221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 16601221 - 2⁷ = 16601093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16601227) 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, 91125 + ... + 91306.

It is an arithmetic number, because the mean of its divisors is an integer number (2554048).

Almost surely, 2^16601221 is an apocalyptic number.

It is an amenable number.

16601221 is a deficient number, since it is larger than the sum of its proper divisors (3831163).

16601221 is a wasteful number, since it uses less digits than its factorization.

16601221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182451.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 16601221 is about 4074.4595960692. The cubic root of 16601221 is about 255.1016946685.

Adding to 16601221 its reverse (12210661), we get a palindrome (28811882).

The spelling of 16601221 in words is "sixteen million, six hundred one thousand, two hundred twenty-one".