8511779681 has 2 divisors, whose sum is σ = 8511779682. Its totient is φ = 8511779680.

The previous prime is 8511779659. The next prime is 8511779687. The reversal of 8511779681 is 1869771158.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4416931600 + 4094848081 = 66460^2 + 63991^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8511779681 is a prime.

It is a super-2 number, since 2×8511779681² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (8511779687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4255889840 + 4255889841.

It is an arithmetic number, because the mean of its divisors is an integer number (4255889841).

Almost surely, 2^8511779681 is an apocalyptic number.

It is an amenable number.

8511779681 is a deficient number, since it is larger than the sum of its proper divisors (1).

8511779681 is an equidigital number, since it uses as much as digits as its factorization.

8511779681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 846720, while the sum is 53.

The square root of 8511779681 is about 92259.3067446315. The cubic root of 8511779681 is about 2041.7698725545.

The spelling of 8511779681 in words is "eight billion, five hundred eleven million, seven hundred seventy-nine thousand, six hundred eighty-one".