216656667 has 8 divisors (see below), whose sum is σ = 320972880. Its totient is φ = 144437760.

The previous prime is 216656647. The next prime is 216656717. The reversal of 216656667 is 766656612.

It is not a de Polignac number, because 216656667 - 2⁶ = 216656603 is a prime.

It is a super-2 number, since 2×216656667² = 93880222711097778, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (216656647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4012134 + ... + 4012187.

It is an arithmetic number, because the mean of its divisors is an integer number (40121610).

Almost surely, 2^216656667 is an apocalyptic number.

216656667 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

216656667 is a deficient number, since it is larger than the sum of its proper divisors (104316213).

216656667 is an equidigital number, since it uses as much as digits as its factorization.

216656667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8024330 (or 8024324 counting only the distinct ones).

The product of its digits is 544320, while the sum is 45.

The square root of 216656667 is about 14719.2617681730. The cubic root of 216656667 is about 600.6074098812.

Subtracting 216656667 from its reverse (766656612), we obtain a palindrome (549999945).

The spelling of 216656667 in words is "two hundred sixteen million, six hundred fifty-six thousand, six hundred sixty-seven".