218214721447 has 4 divisors (see below), whose sum is σ = 221471657656. Its totient is φ = 214957785240.

The previous prime is 218214721433. The next prime is 218214721457. The reversal of 218214721447 is 744127412812.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-218214721447 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 (218214721457) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1628468004 + ... + 1628468137.

It is an arithmetic number, because the mean of its divisors is an integer number (55367914414).

Almost surely, 2^218214721447 is an apocalyptic number.

218214721447 is a deficient number, since it is larger than the sum of its proper divisors (3256936209).

218214721447 is an equidigital number, since it uses as much as digits as its factorization.

218214721447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3256936208.

The product of its digits is 200704, while the sum is 43.

The spelling of 218214721447 in words is "two hundred eighteen billion, two hundred fourteen million, seven hundred twenty-one thousand, four hundred forty-seven".