16366221 has 6 divisors (see below), whose sum is σ = 23640110. Its totient is φ = 10910808.

The previous prime is 16366219. The next prime is 16366249. The reversal of 16366221 is 12266361.

16366221 is a `hidden beast` number, since 1 + 6 + 36 + 622 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 8328996 + 8037225 = 2886^2 + 2835^2 .

It is not a de Polignac number, because 16366221 - 2¹ = 16366219 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16366211) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 909226 + ... + 909243.

Almost surely, 2^16366221 is an apocalyptic number.

It is an amenable number.

16366221 is a deficient number, since it is larger than the sum of its proper divisors (7273889).

16366221 is a wasteful number, since it uses less digits than its factorization.

16366221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1818475 (or 1818472 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 16366221 is about 4045.5186317702. The cubic root of 16366221 is about 253.8922652618.

The spelling of 16366221 in words is "sixteen million, three hundred sixty-six thousand, two hundred twenty-one".