20779688173 has 2 divisors, whose sum is σ = 20779688174. Its totient is φ = 20779688172.

The previous prime is 20779688147. The next prime is 20779688191. The reversal of 20779688173 is 37188697702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20322498249 + 457189924 = 142557^2 + 21382^2 .

It is a cyclic number.

It is not a de Polignac number, because 20779688173 - 2²⁵ = 20746133741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20779682173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10389844086 + 10389844087.

It is an arithmetic number, because the mean of its divisors is an integer number (10389844087).

Almost surely, 2^20779688173 is an apocalyptic number.

It is an amenable number.

20779688173 is a deficient number, since it is larger than the sum of its proper divisors (1).

20779688173 is an equidigital number, since it uses as much as digits as its factorization.

20779688173 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7112448, while the sum is 58.

The spelling of 20779688173 in words is "twenty billion, seven hundred seventy-nine million, six hundred eighty-eight thousand, one hundred seventy-three".