216142786721 has 2 divisors, whose sum is σ = 216142786722. Its totient is φ = 216142786720.

The previous prime is 216142786681. The next prime is 216142786723. The reversal of 216142786721 is 127687241612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212738647696 + 3404139025 = 461236^2 + 58345^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216142786721 is a prime.

Together with 216142786723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (216142786723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108071393360 + 108071393361.

It is an arithmetic number, because the mean of its divisors is an integer number (108071393361).

Almost surely, 2^216142786721 is an apocalyptic number.

It is an amenable number.

216142786721 is a deficient number, since it is larger than the sum of its proper divisors (1).

216142786721 is an equidigital number, since it uses as much as digits as its factorization.

216142786721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 451584, while the sum is 47.

The spelling of 216142786721 in words is "two hundred sixteen billion, one hundred forty-two million, seven hundred eighty-six thousand, seven hundred twenty-one".