20766780757 has 2 divisors, whose sum is σ = 20766780758. Its totient is φ = 20766780756.

The previous prime is 20766780737. The next prime is 20766780767. The reversal of 20766780757 is 75708766702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13945011921 + 6821768836 = 118089^2 + 82594^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20766780757 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20766780698 and 20766780707.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20766780737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10383390378 + 10383390379.

It is an arithmetic number, because the mean of its divisors is an integer number (10383390379).

Almost surely, 2^20766780757 is an apocalyptic number.

It is an amenable number.

20766780757 is a deficient number, since it is larger than the sum of its proper divisors (1).

20766780757 is an equidigital number, since it uses as much as digits as its factorization.

20766780757 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6914880, while the sum is 55.

The spelling of 20766780757 in words is "twenty billion, seven hundred sixty-six million, seven hundred eighty thousand, seven hundred fifty-seven".