2128340639 has 4 divisors (see below), whose sum is σ = 2129642424. Its totient is φ = 2127038856.

The previous prime is 2128340587. The next prime is 2128340647. The reversal of 2128340639 is 9360438212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2128340639 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2128340699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 648437 + ... + 651710.

It is an arithmetic number, because the mean of its divisors is an integer number (532410606).

Almost surely, 2^2128340639 is an apocalyptic number.

2128340639 is a deficient number, since it is larger than the sum of its proper divisors (1301785).

2128340639 is a wasteful number, since it uses less digits than its factorization.

2128340639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1301784.

The product of its (nonzero) digits is 62208, while the sum is 38.

The square root of 2128340639 is about 46133.9423743517. The cubic root of 2128340639 is about 1286.3141464104.

The spelling of 2128340639 in words is "two billion, one hundred twenty-eight million, three hundred forty thousand, six hundred thirty-nine".