217991364889 has 16 divisors (see below), whose sum is σ = 231373702080. Its totient is φ = 204805972800.

The previous prime is 217991364863. The next prime is 217991364917. The reversal of 217991364889 is 988463199712.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 217991364889 - 2¹³ = 217991356697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217991364989) 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, 1221414 + ... + 1388464.

It is an arithmetic number, because the mean of its divisors is an integer number (14460856380).

Almost surely, 2^217991364889 is an apocalyptic number.

It is an amenable number.

217991364889 is a deficient number, since it is larger than the sum of its proper divisors (13382337191).

217991364889 is a wasteful number, since it uses less digits than its factorization.

217991364889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167640.

The product of its digits is 47029248, while the sum is 67.

The spelling of 217991364889 in words is "two hundred seventeen billion, nine hundred ninety-one million, three hundred sixty-four thousand, eight hundred eighty-nine".