217839780216 has 64 divisors (see below), whose sum is σ = 631419667200. Its totient is φ = 69456160224.

The previous prime is 217839780181. The next prime is 217839780217. The reversal of 217839780216 is 612087938712.

It is a happy number.

217839780216 is a `hidden beast` number, since 2 + 178 + 397 + 80 + 2 + 1 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217839780217) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21919326 + ... + 21929261.

It is an arithmetic number, because the mean of its divisors is an integer number (9865932300).

Almost surely, 2^217839780216 is an apocalyptic number.

It is an amenable number.

217839780216 is an abundant number, since it is smaller than the sum of its proper divisors (413579886984).

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

217839780216 is a wasteful number, since it uses less digits than its factorization.

217839780216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43848625 (or 43848615 counting only the distinct ones).

The product of its (nonzero) digits is 2032128, while the sum is 54.

The spelling of 217839780216 in words is "two hundred seventeen billion, eight hundred thirty-nine million, seven hundred eighty thousand, two hundred sixteen".