20784123761 has 2 divisors, whose sum is σ = 20784123762. Its totient is φ = 20784123760.

The previous prime is 20784123743. The next prime is 20784123793. The reversal of 20784123761 is 16732148702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15651261025 + 5132862736 = 125105^2 + 71644^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20784123761 is a prime.

It is not a weakly prime, because it can be changed into another prime (20784120761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10392061880 + 10392061881.

It is an arithmetic number, because the mean of its divisors is an integer number (10392061881).

Almost surely, 2^20784123761 is an apocalyptic number.

It is an amenable number.

20784123761 is a deficient number, since it is larger than the sum of its proper divisors (1).

20784123761 is an equidigital number, since it uses as much as digits as its factorization.

20784123761 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112896, while the sum is 41.

The spelling of 20784123761 in words is "twenty billion, seven hundred eighty-four million, one hundred twenty-three thousand, seven hundred sixty-one".