216487875991 has 4 divisors (see below), whose sum is σ = 216509790952. Its totient is φ = 216465961032.

The previous prime is 216487875979. The next prime is 216487876009. The reversal of 216487875991 is 199578784612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 216487875991 - 2¹⁵ = 216487843223 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 (216487875911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10942656 + ... + 10962421.

It is an arithmetic number, because the mean of its divisors is an integer number (54127447738).

Almost surely, 2^216487875991 is an apocalyptic number.

216487875991 is a deficient number, since it is larger than the sum of its proper divisors (21914961).

216487875991 is an equidigital number, since it uses as much as digits as its factorization.

216487875991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21914960.

The product of its digits is 60963840, while the sum is 67.

The spelling of 216487875991 in words is "two hundred sixteen billion, four hundred eighty-seven million, eight hundred seventy-five thousand, nine hundred ninety-one".