2185806643 has 4 divisors (see below), whose sum is σ = 2194515288. Its totient is φ = 2177098000.

The previous prime is 2185806631. The next prime is 2185806653. The reversal of 2185806643 is 3466085812.

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

It is a cyclic number.

It is not a de Polignac number, because 2185806643 - 2⁹ = 2185806131 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2185806643.

It is not an unprimeable number, because it can be changed into a prime (2185806653) 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, 4353946 + ... + 4354447.

It is an arithmetic number, because the mean of its divisors is an integer number (548628822).

Almost surely, 2^2185806643 is an apocalyptic number.

2185806643 is a deficient number, since it is larger than the sum of its proper divisors (8708645).

2185806643 is an equidigital number, since it uses as much as digits as its factorization.

2185806643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8708644.

The product of its (nonzero) digits is 276480, while the sum is 43.

The square root of 2185806643 is about 46752.6110821631. The cubic root of 2185806643 is about 1297.7884772323.

The spelling of 2185806643 in words is "two billion, one hundred eighty-five million, eight hundred six thousand, six hundred forty-three".