2643561685 has 4 divisors (see below), whose sum is σ = 3172274028. Its totient is φ = 2114849344.

The previous prime is 2643561677. The next prime is 2643561689. The reversal of 2643561685 is 5861653462.

2643561685 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 361684324 + 2281877361 = 19018^2 + 47769^2 .

It is a cyclic number.

It is not a de Polignac number, because 2643561685 - 2³ = 2643561677 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 (2643561689) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 264356164 + ... + 264356173.

It is an arithmetic number, because the mean of its divisors is an integer number (793068507).

Almost surely, 2^2643561685 is an apocalyptic number.

It is an amenable number.

2643561685 is a deficient number, since it is larger than the sum of its proper divisors (528712343).

2643561685 is an equidigital number, since it uses as much as digits as its factorization.

2643561685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528712342.

The product of its digits is 1036800, while the sum is 46.

The square root of 2643561685 is about 51415.5782326719. The cubic root of 2643561685 is about 1382.7059008130.

The spelling of 2643561685 in words is "two billion, six hundred forty-three million, five hundred sixty-one thousand, six hundred eighty-five".