16690221 has 12 divisors (see below), whose sum is σ = 24399648. Its totient is φ = 10992264.

The previous prime is 16690211. The next prime is 16690229. The reversal of 16690221 is 12209661.

It is not a de Polignac number, because 16690221 - 2¹¹ = 16688173 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16690229) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10425 + ... + 11918.

It is an arithmetic number, because the mean of its divisors is an integer number (2033304).

Almost surely, 2^16690221 is an apocalyptic number.

It is an amenable number.

16690221 is a deficient number, since it is larger than the sum of its proper divisors (7709427).

16690221 is a wasteful number, since it uses less digits than its factorization.

16690221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22432 (or 22429 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 16690221 is about 4085.3666910083. The cubic root of 16690221 is about 255.5567535406.

Adding to 16690221 its reverse (12209661), we get a palindrome (28899882).

The spelling of 16690221 in words is "sixteen million, six hundred ninety thousand, two hundred twenty-one".