851691766689 has 20 divisors (see below), whose sum is σ = 1306666251924. Its totient is φ = 552448711584.

The previous prime is 851691766633. The next prime is 851691766769. The reversal of 851691766689 is 986667196158.

It can be written as a sum of positive squares in 2 ways, for example, as 778241552400 + 73450214289 = 882180^2 + 271017^2 .

It is not a de Polignac number, because 851691766689 - 2¹⁶ = 851691701153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (851691761689) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 142087722 + ... + 142093715.

Almost surely, 2^851691766689 is an apocalyptic number.

It is an amenable number.

851691766689 is a deficient number, since it is larger than the sum of its proper divisors (454974485235).

851691766689 is a wasteful number, since it uses less digits than its factorization.

851691766689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284181486 (or 284181477 counting only the distinct ones).

The product of its digits is 235146240, while the sum is 72.

The spelling of 851691766689 in words is "eight hundred fifty-one billion, six hundred ninety-one million, seven hundred sixty-six thousand, six hundred eighty-nine".