216488666 has 4 divisors (see below), whose sum is σ = 324733002. Its totient is φ = 108244332.

The previous prime is 216488663. The next prime is 216488681. The reversal of 216488666 is 666884612.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 152152225 + 64336441 = 12335^2 + 8021^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 216488666.

It is not an unprimeable number, because it can be changed into a prime (216488663) 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 as a sum of consecutive naturals, namely, 54122165 + ... + 54122168.

Almost surely, 2^216488666 is an apocalyptic number.

216488666 is a deficient number, since it is larger than the sum of its proper divisors (108244336).

216488666 is a wasteful number, since it uses less digits than its factorization.

216488666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108244335.

The product of its digits is 663552, while the sum is 47.

The square root of 216488666 is about 14713.5538195230. The cubic root of 216488666 is about 600.4521277338.

The spelling of 216488666 in words is "two hundred sixteen million, four hundred eighty-eight thousand, six hundred sixty-six".