218400718306021 has 16 divisors (see below), whose sum is σ = 223870643107840. Its totient is φ = 212993890562880.

The previous prime is 218400718305953. The next prime is 218400718306039. The reversal of 218400718306021 is 120603817004812.

It is a cyclic number.

It is not a de Polignac number, because 218400718306021 - 2⁹ = 218400718305509 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 (218400718306081) 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, 3305455 + ... + 21159571.

It is an arithmetic number, because the mean of its divisors is an integer number (13991915194240).

Almost surely, 2^{218400718306021} is an apocalyptic number.

It is an amenable number.

218400718306021 is a deficient number, since it is larger than the sum of its proper divisors (5469924801819).

218400718306021 is a wasteful number, since it uses less digits than its factorization.

218400718306021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17855884.

The product of its (nonzero) digits is 129024, while the sum is 43.

The spelling of 218400718306021 in words is "two hundred eighteen trillion, four hundred billion, seven hundred eighteen million, three hundred six thousand, twenty-one".