216664478 has 8 divisors (see below), whose sum is σ = 325792560. Its totient is φ = 108066960.

The previous prime is 216664471. The next prime is 216664561. The reversal of 216664478 is 874466612.

216664478 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216664471) 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, 131618 + ... + 133253.

It is an arithmetic number, because the mean of its divisors is an integer number (40724070).

Almost surely, 2^216664478 is an apocalyptic number.

216664478 is a deficient number, since it is larger than the sum of its proper divisors (109128082).

216664478 is a wasteful number, since it uses less digits than its factorization.

216664478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265282.

The product of its digits is 387072, while the sum is 44.

The square root of 216664478 is about 14719.5270983819. The cubic root of 216664478 is about 600.6146275806.

The spelling of 216664478 in words is "two hundred sixteen million, six hundred sixty-four thousand, four hundred seventy-eight".