218121826057 has 4 divisors (see below), whose sum is σ = 218141317636. Its totient is φ = 218102334480.

The previous prime is 218121826007. The next prime is 218121826063. The reversal of 218121826057 is 750628121812.

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 79865020816 + 138256805241 = 282604^2 + 371829^2 .

It is a cyclic number.

It is not a de Polignac number, because 218121826057 - 2¹¹ = 218121824009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218121826007) 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, 9728994 + ... + 9751387.

It is an arithmetic number, because the mean of its divisors is an integer number (54535329409).

Almost surely, 2^218121826057 is an apocalyptic number.

It is an amenable number.

218121826057 is a deficient number, since it is larger than the sum of its proper divisors (19491579).

218121826057 is a wasteful number, since it uses less digits than its factorization.

218121826057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19491578.

The product of its (nonzero) digits is 107520, while the sum is 43.

Adding to 218121826057 its reverse (750628121812), we get a palindrome (968749947869).

The spelling of 218121826057 in words is "two hundred eighteen billion, one hundred twenty-one million, eight hundred twenty-six thousand, fifty-seven".