217768138 has 16 divisors (see below), whose sum is σ = 382423104. Its totient is φ = 91052640.

The previous prime is 217768129. The next prime is 217768141. The reversal of 217768138 is 831867712.

It is a junction number, because it is equal to n+sod(n) for n = 217768094 and 217768103.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 189120 + ... + 190267.

It is an arithmetic number, because the mean of its divisors is an integer number (23901444).

Almost surely, 2^217768138 is an apocalyptic number.

217768138 is a deficient number, since it is larger than the sum of its proper divisors (164654966).

217768138 is a wasteful number, since it uses less digits than its factorization.

217768138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379437.

The product of its digits is 112896, while the sum is 43.

The square root of 217768138 is about 14756.9691332604. The cubic root of 217768138 is about 601.6327178389.

The spelling of 217768138 in words is "two hundred seventeen million, seven hundred sixty-eight thousand, one hundred thirty-eight".