218844444661 has 4 divisors (see below), whose sum is σ = 218861775052. Its totient is φ = 218827114272.

The previous prime is 218844444649. The next prime is 218844444683. The reversal of 218844444661 is 166444448812.

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

It can be written as a sum of positive squares in 2 ways, for example, as 97535037636 + 121309407025 = 312306^2 + 348295^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-218844444661 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 218844444599 and 218844444608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218844444631) 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, 8646240 + ... + 8671513.

It is an arithmetic number, because the mean of its divisors is an integer number (54715443763).

Almost surely, 2^218844444661 is an apocalyptic number.

It is an amenable number.

218844444661 is a deficient number, since it is larger than the sum of its proper divisors (17330391).

218844444661 is a wasteful number, since it uses less digits than its factorization.

218844444661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17330390.

The product of its digits is 4718592, while the sum is 52.

The spelling of 218844444661 in words is "two hundred eighteen billion, eight hundred forty-four million, four hundred forty-four thousand, six hundred sixty-one".