216664879 has 2 divisors, whose sum is σ = 216664880. Its totient is φ = 216664878.

The previous prime is 216664873. The next prime is 216664909. The reversal of 216664879 is 978466612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 216664879 - 2³ = 216664871 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216664871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108332439 + 108332440.

It is an arithmetic number, because the mean of its divisors is an integer number (108332440).

Almost surely, 2^216664879 is an apocalyptic number.

216664879 is a deficient number, since it is larger than the sum of its proper divisors (1).

216664879 is an equidigital number, since it uses as much as digits as its factorization.

216664879 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 870912, while the sum is 49.

The square root of 216664879 is about 14719.5407197371. The cubic root of 216664879 is about 600.6149981172.

The spelling of 216664879 in words is "two hundred sixteen million, six hundred sixty-four thousand, eight hundred seventy-nine".