2180801809 has 4 divisors (see below), whose sum is σ = 2183777716. Its totient is φ = 2177825904.

The previous prime is 2180801807. The next prime is 2180801839. The reversal of 2180801809 is 9081080812.

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 2101947409 + 78854400 = 45847^2 + 8880^2 .

It is a cyclic number.

It is not a de Polignac number, because 2180801809 - 2¹ = 2180801807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2180801807) 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, 1486854 + ... + 1488319.

It is an arithmetic number, because the mean of its divisors is an integer number (545944429).

Almost surely, 2^2180801809 is an apocalyptic number.

It is an amenable number.

2180801809 is a deficient number, since it is larger than the sum of its proper divisors (2975907).

2180801809 is an equidigital number, since it uses as much as digits as its factorization.

2180801809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2975906.

The product of its (nonzero) digits is 9216, while the sum is 37.

The square root of 2180801809 is about 46699.0557613320. The cubic root of 2180801809 is about 1296.7972063301.

The spelling of 2180801809 in words is "two billion, one hundred eighty million, eight hundred one thousand, eight hundred nine".