8505661973 has 2 divisors, whose sum is σ = 8505661974. Its totient is φ = 8505661972.

The previous prime is 8505661963. The next prime is 8505661979. The reversal of 8505661973 is 3791665058.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8104140529 + 401521444 = 90023^2 + 20038^2 .

It is a cyclic number.

It is not a de Polignac number, because 8505661973 - 2¹² = 8505657877 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8505661979) 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, 4252830986 + 4252830987.

It is an arithmetic number, because the mean of its divisors is an integer number (4252830987).

Almost surely, 2^8505661973 is an apocalyptic number.

It is an amenable number.

8505661973 is a deficient number, since it is larger than the sum of its proper divisors (1).

8505661973 is an equidigital number, since it uses as much as digits as its factorization.

8505661973 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1360800, while the sum is 50.

The square root of 8505661973 is about 92226.1458210198. The cubic root of 8505661973 is about 2041.2805919691.

The spelling of 8505661973 in words is "eight billion, five hundred five million, six hundred sixty-one thousand, nine hundred seventy-three".