2179809809 has 2 divisors, whose sum is σ = 2179809810. Its totient is φ = 2179809808.

The previous prime is 2179809803. The next prime is 2179809817. The reversal of 2179809809 is 9089089712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1298016784 + 881793025 = 36028^2 + 29695^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2179809809 is a prime.

It is not a weakly prime, because it can be changed into another prime (2179809803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1089904904 + 1089904905.

It is an arithmetic number, because the mean of its divisors is an integer number (1089904905).

Almost surely, 2^2179809809 is an apocalyptic number.

It is an amenable number.

2179809809 is a deficient number, since it is larger than the sum of its proper divisors (1).

2179809809 is an equidigital number, since it uses as much as digits as its factorization.

2179809809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 653184, while the sum is 53.

The square root of 2179809809 is about 46688.4333534549. The cubic root of 2179809809 is about 1296.6005480906.

The spelling of 2179809809 in words is "two billion, one hundred seventy-nine million, eight hundred nine thousand, eight hundred nine".