775756657561 has 2 divisors, whose sum is σ = 775756657562. Its totient is φ = 775756657560.

The previous prime is 775756657549. The next prime is 775756657591. The reversal of 775756657561 is 165756657577.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 772931097225 + 2825560336 = 879165^2 + 53156^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-775756657561 is a prime.

It is not a weakly prime, because it can be changed into another prime (775756657541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 387878328780 + 387878328781.

It is an arithmetic number, because the mean of its divisors is an integer number (387878328781).

Almost surely, 2^775756657561 is an apocalyptic number.

It is an amenable number.

775756657561 is a deficient number, since it is larger than the sum of its proper divisors (1).

775756657561 is an equidigital number, since it uses as much as digits as its factorization.

775756657561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 324135000, while the sum is 67.

The spelling of 775756657561 in words is "seven hundred seventy-five billion, seven hundred fifty-six million, six hundred fifty-seven thousand, five hundred sixty-one".