2128656745 has 4 divisors (see below), whose sum is σ = 2554388100. Its totient is φ = 1702925392.

The previous prime is 2128656721. The next prime is 2128656767. The reversal of 2128656745 is 5476568212.

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 410305536 + 1718351209 = 20256^2 + 41453^2 .

It is a cyclic number.

It is not a de Polignac number, because 2128656745 - 2⁷ = 2128656617 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2128656695 and 2128656704.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 212865670 + ... + 212865679.

It is an arithmetic number, because the mean of its divisors is an integer number (638597025).

Almost surely, 2^2128656745 is an apocalyptic number.

It is an amenable number.

2128656745 is a deficient number, since it is larger than the sum of its proper divisors (425731355).

2128656745 is an equidigital number, since it uses as much as digits as its factorization.

2128656745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 425731354.

The product of its digits is 806400, while the sum is 46.

The square root of 2128656745 is about 46137.3682062599. The cubic root of 2128656745 is about 1286.3778253603.

The spelling of 2128656745 in words is "two billion, one hundred twenty-eight million, six hundred fifty-six thousand, seven hundred forty-five".