20765992777 has 2 divisors, whose sum is σ = 20765992778. Its totient is φ = 20765992776.

The previous prime is 20765992721. The next prime is 20765992783. The reversal of 20765992777 is 77729956702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16389376441 + 4376616336 = 128021^2 + 66156^2 .

It is a cyclic number.

It is not a de Polignac number, because 20765992777 - 2¹⁵ = 20765960009 is a prime.

It is not a weakly prime, because it can be changed into another prime (20765992717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10382996388 + 10382996389.

It is an arithmetic number, because the mean of its divisors is an integer number (10382996389).

Almost surely, 2^20765992777 is an apocalyptic number.

It is an amenable number.

20765992777 is a deficient number, since it is larger than the sum of its proper divisors (1).

20765992777 is an equidigital number, since it uses as much as digits as its factorization.

20765992777 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23337720, while the sum is 61.

The spelling of 20765992777 in words is "twenty billion, seven hundred sixty-five million, nine hundred ninety-two thousand, seven hundred seventy-seven".