16661219 has 4 divisors (see below), whose sum is σ = 16705560. Its totient is φ = 16616880.

The previous prime is 16661213. The next prime is 16661221. The reversal of 16661219 is 91216661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16661219 is a prime.

It is a super-2 number, since 2×16661219² = 555192437131922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16661213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21602 + ... + 22359.

It is an arithmetic number, because the mean of its divisors is an integer number (4176390).

Almost surely, 2^16661219 is an apocalyptic number.

16661219 is a deficient number, since it is larger than the sum of its proper divisors (44341).

16661219 is an equidigital number, since it uses as much as digits as its factorization.

16661219 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44340.

The product of its digits is 3888, while the sum is 32.

The square root of 16661219 is about 4081.8156499284. The cubic root of 16661219 is about 255.4086437760.

The spelling of 16661219 in words is "sixteen million, six hundred sixty-one thousand, two hundred nineteen".