20209966647779 has 2 divisors, whose sum is σ = 20209966647780. Its totient is φ = 20209966647778.

The previous prime is 20209966647743. The next prime is 20209966647791. The reversal of 20209966647779 is 97774666990202.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20209966647779 - 2²⁴ = 20209949870563 is a prime.

It is not a weakly prime, because it can be changed into another prime (20209966647379) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10104983323889 + 10104983323890.

It is an arithmetic number, because the mean of its divisors is an integer number (10104983323890).

Almost surely, 2^{20209966647779} is an apocalyptic number.

20209966647779 is a deficient number, since it is larger than the sum of its proper divisors (1).

20209966647779 is an equidigital number, since it uses as much as digits as its factorization.

20209966647779 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864162432, while the sum is 74.

The spelling of 20209966647779 in words is "twenty trillion, two hundred nine billion, nine hundred sixty-six million, six hundred forty-seven thousand, seven hundred seventy-nine".