217290638879 has 16 divisors (see below), whose sum is σ = 238067449920. Its totient is φ = 197405806080.

The previous prime is 217290638869. The next prime is 217290638891. The reversal of 217290638879 is 978836092712.

It is a de Polignac number, because none of the positive numbers 2^k-217290638879 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217290638849) 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 in 15 ways as a sum of consecutive naturals, for example, 1923494 + ... + 2033324.

It is an arithmetic number, because the mean of its divisors is an integer number (14879215620).

Almost surely, 2^217290638879 is an apocalyptic number.

217290638879 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

217290638879 is a deficient number, since it is larger than the sum of its proper divisors (20776811041).

217290638879 is a wasteful number, since it uses less digits than its factorization.

217290638879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113890.

The product of its (nonzero) digits is 18289152, while the sum is 62.

The spelling of 217290638879 in words is "two hundred seventeen billion, two hundred ninety million, six hundred thirty-eight thousand, eight hundred seventy-nine".