16609021 has 16 divisors (see below), whose sum is σ = 20543040. Its totient is φ = 13201920.

The previous prime is 16608989. The next prime is 16609027. The reversal of 16609021 is 12090661.

It is a cyclic number.

It is not a de Polignac number, because 16609021 - 2⁵ = 16608989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16609027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 340 + ... + 5773.

It is an arithmetic number, because the mean of its divisors is an integer number (1283940).

Almost surely, 2^16609021 is an apocalyptic number.

16609021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16609021 is a deficient number, since it is larger than the sum of its proper divisors (3934019).

16609021 is a wasteful number, since it uses less digits than its factorization.

16609021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6156.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 16609021 is about 4075.4166658147. The cubic root of 16609021 is about 255.1416411614.

Adding to 16609021 its reverse (12090661), we get a palindrome (28699682).

The spelling of 16609021 in words is "sixteen million, six hundred nine thousand, twenty-one".