216646669 has 4 divisors (see below), whose sum is σ = 220734396. Its totient is φ = 212558944.

The previous prime is 216646663. The next prime is 216646679. The reversal of 216646669 is 966646612.

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

It can be written as a sum of positive squares in 2 ways, for example, as 100761444 + 115885225 = 10038^2 + 10765^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216646669 is a prime.

It is a super-2 number, since 2×216646669² = 93871558377591122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216646663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2043784 + ... + 2043889.

It is an arithmetic number, because the mean of its divisors is an integer number (55183599).

Almost surely, 2^216646669 is an apocalyptic number.

It is an amenable number.

216646669 is a deficient number, since it is larger than the sum of its proper divisors (4087727).

216646669 is an equidigital number, since it uses as much as digits as its factorization.

216646669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4087726.

The product of its digits is 559872, while the sum is 46.

The square root of 216646669 is about 14718.9221412439. The cubic root of 216646669 is about 600.5981710467.

The spelling of 216646669 in words is "two hundred sixteen million, six hundred forty-six thousand, six hundred sixty-nine".