2128206985 has 4 divisors (see below), whose sum is σ = 2553848388. Its totient is φ = 1702565584.

The previous prime is 2128206919. The next prime is 2128207001. The reversal of 2128206985 is 5896028212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 294740224 + 1833466761 = 17168^2 + 42819^2 .

It is a cyclic number.

It is not a de Polignac number, because 2128206985 - 2¹⁷ = 2128075913 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 212820694 + ... + 212820703.

It is an arithmetic number, because the mean of its divisors is an integer number (638462097).

Almost surely, 2^2128206985 is an apocalyptic number.

It is an amenable number.

2128206985 is a deficient number, since it is larger than the sum of its proper divisors (425641403).

2128206985 is an equidigital number, since it uses as much as digits as its factorization.

2128206985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425641402.

The product of its (nonzero) digits is 138240, while the sum is 43.

The square root of 2128206985 is about 46132.4938085944. The cubic root of 2128206985 is about 1286.2872201708.

The spelling of 2128206985 in words is "two billion, one hundred twenty-eight million, two hundred six thousand, nine hundred eighty-five".