20657184809 has 2 divisors, whose sum is σ = 20657184810. Its totient is φ = 20657184808.

The previous prime is 20657184733. The next prime is 20657184853. The reversal of 20657184809 is 90848175602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20333904409 + 323280400 = 142597^2 + 17980^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20657184809 is a prime.

It is not a weakly prime, because it can be changed into another prime (20657184859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10328592404 + 10328592405.

It is an arithmetic number, because the mean of its divisors is an integer number (10328592405).

Almost surely, 2^20657184809 is an apocalyptic number.

It is an amenable number.

20657184809 is a deficient number, since it is larger than the sum of its proper divisors (1).

20657184809 is an equidigital number, since it uses as much as digits as its factorization.

20657184809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 967680, while the sum is 50.

The spelling of 20657184809 in words is "twenty billion, six hundred fifty-seven million, one hundred eighty-four thousand, eight hundred nine".