216666775720 has 16 divisors (see below), whose sum is σ = 487500245460. Its totient is φ = 86666710272.

The previous prime is 216666775681. The next prime is 216666775729. The reversal of 216666775720 is 27577666612.

It can be written as a sum of positive squares in 2 ways, for example, as 195907152996 + 20759622724 = 442614^2 + 144082^2 .

It is not an unprimeable number, because it can be changed into a prime (216666775729) 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, 2708334657 + ... + 2708334736.

Almost surely, 2^216666775720 is an apocalyptic number.

216666775720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216666775720 is an abundant number, since it is smaller than the sum of its proper divisors (270833469740).

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

216666775720 is a wasteful number, since it uses less digits than its factorization.

216666775720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5416669404 (or 5416669400 counting only the distinct ones).

The product of its (nonzero) digits is 8890560, while the sum is 55.

The spelling of 216666775720 in words is "two hundred sixteen billion, six hundred sixty-six million, seven hundred seventy-five thousand, seven hundred twenty".