775757791661 has 2 divisors, whose sum is σ = 775757791662. Its totient is φ = 775757791660.

The previous prime is 775757791657. The next prime is 775757791717. The reversal of 775757791661 is 166197757577.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 743571637636 + 32186154025 = 862306^2 + 179405^2 .

It is a cyclic number.

It is not a de Polignac number, because 775757791661 - 2² = 775757791657 is a prime.

It is a super-2 number, since 2×775757791661² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 775757791591 and 775757791600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (775757791631) 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, 387878895830 + 387878895831.

It is an arithmetic number, because the mean of its divisors is an integer number (387878895831).

Almost surely, 2^775757791661 is an apocalyptic number.

It is an amenable number.

775757791661 is a deficient number, since it is larger than the sum of its proper divisors (1).

775757791661 is an equidigital number, since it uses as much as digits as its factorization.

775757791661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 136136700, while the sum is 68.

The spelling of 775757791661 in words is "seven hundred seventy-five billion, seven hundred fifty-seven million, seven hundred ninety-one thousand, six hundred sixty-one".