666663216 has 20 divisors (see below), whose sum is σ = 1722213432. Its totient is φ = 222221056.

The previous prime is 666663167. The next prime is 666663247. The reversal of 666663216 is 612366666.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6944361 + ... + 6944456.

Almost surely, 2^666663216 is an apocalyptic number.

It is an amenable number.

666663216 is an abundant number, since it is smaller than the sum of its proper divisors (1055550216).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

666663216 is a wasteful number, since it uses less digits than its factorization.

666663216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13888828 (or 13888822 counting only the distinct ones).

The product of its digits is 279936, while the sum is 42.

The square root of 666663216 is about 25819.8221527570. The cubic root of 666663216 is about 873.5789575162.

The spelling of 666663216 in words is "six hundred sixty-six million, six hundred sixty-three thousand, two hundred sixteen".