216778257618 has 16 divisors (see below), whose sum is σ = 466907016576. Its totient is φ = 66701002320.

The previous prime is 216778257613. The next prime is 216778257623. The reversal of 216778257618 is 816752877612.

It is an interprime number because it is at equal distance from previous prime (216778257613) and next prime (216778257623).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (216778257611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1389604138 + ... + 1389604293.

It is an arithmetic number, because the mean of its divisors is an integer number (29181688536).

Almost surely, 2^216778257618 is an apocalyptic number.

216778257618 is an abundant number, since it is smaller than the sum of its proper divisors (250128758958).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216778257618 is a wasteful number, since it uses less digits than its factorization.

216778257618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2779208449.

The product of its digits is 15805440, while the sum is 60.

The spelling of 216778257618 in words is "two hundred sixteen billion, seven hundred seventy-eight million, two hundred fifty-seven thousand, six hundred eighteen".