217678066 has 4 divisors (see below), whose sum is σ = 326517102. Its totient is φ = 108839032.

The previous prime is 217678051. The next prime is 217678099. The reversal of 217678066 is 660876712.

217678066 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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., 216707841 + 970225 = 14721^2 + 985^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54419515 + ... + 54419518.

Almost surely, 2^217678066 is an apocalyptic number.

217678066 is a deficient number, since it is larger than the sum of its proper divisors (108839036).

217678066 is a wasteful number, since it uses less digits than its factorization.

217678066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108839035.

The product of its (nonzero) digits is 169344, while the sum is 43.

The square root of 217678066 is about 14753.9169714351. The cubic root of 217678066 is about 601.5497584496.

The spelling of 217678066 in words is "two hundred seventeen million, six hundred seventy-eight thousand, sixty-six".