16626221 has 8 divisors (see below), whose sum is σ = 17893944. Its totient is φ = 15390720.

The previous prime is 16626173. The next prime is 16626223. The reversal of 16626221 is 12262661.

It can be written as a sum of positive squares in 4 ways, for example, as 264196 + 16362025 = 514^2 + 4045^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16626221 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 (16626223) 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, 6980 + ... + 9053.

It is an arithmetic number, because the mean of its divisors is an integer number (2236743).

Almost surely, 2^16626221 is an apocalyptic number.

It is an amenable number.

16626221 is a deficient number, since it is larger than the sum of its proper divisors (1267723).

16626221 is a wasteful number, since it uses less digits than its factorization.

16626221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16111.

The product of its digits is 1728, while the sum is 26.

The square root of 16626221 is about 4077.5263334527. The cubic root of 16626221 is about 255.2296841239.

Adding to 16626221 its reverse (12262661), we get a palindrome (28888882).

The spelling of 16626221 in words is "sixteen million, six hundred twenty-six thousand, two hundred twenty-one".