2128218817 has 2 divisors, whose sum is σ = 2128218818. Its totient is φ = 2128218816.

The previous prime is 2128218811. The next prime is 2128218871. The reversal of 2128218817 is 7188128212.

Together with next prime (2128218871) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1904536881 + 223681936 = 43641^2 + 14956^2 .

It is a cyclic number.

It is not a de Polignac number, because 2128218817 - 2³ = 2128218809 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2128218817.

It is not a weakly prime, because it can be changed into another prime (2128218811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1064109408 + 1064109409.

It is an arithmetic number, because the mean of its divisors is an integer number (1064109409).

Almost surely, 2^2128218817 is an apocalyptic number.

It is an amenable number.

2128218817 is a deficient number, since it is larger than the sum of its proper divisors (1).

2128218817 is an equidigital number, since it uses as much as digits as its factorization.

2128218817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28672, while the sum is 40.

The square root of 2128218817 is about 46132.6220477440. The cubic root of 2128218817 is about 1286.2896039180.

The spelling of 2128218817 in words is "two billion, one hundred twenty-eight million, two hundred eighteen thousand, eight hundred seventeen".