218421911491 has 16 divisors (see below), whose sum is σ = 255459559168. Its totient is φ = 182843892000.

The previous prime is 218421911471. The next prime is 218421911531. The reversal of 218421911491 is 194119124812.

It is not a de Polignac number, because 218421911491 - 2⁵ = 218421911459 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218421911431) 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, 2943556 + ... + 3016846.

It is an arithmetic number, because the mean of its divisors is an integer number (15966222448).

Almost surely, 2^218421911491 is an apocalyptic number.

218421911491 is a deficient number, since it is larger than the sum of its proper divisors (37037647677).

218421911491 is an equidigital number, since it uses as much as digits as its factorization.

218421911491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83242.

The product of its digits is 41472, while the sum is 43.

The spelling of 218421911491 in words is "two hundred eighteen billion, four hundred twenty-one million, nine hundred eleven thousand, four hundred ninety-one".