6851785521 has 16 divisors (see below), whose sum is σ = 10517030784. Its totient is φ = 3886725504.

The previous prime is 6851785471. The next prime is 6851785531. The reversal of 6851785521 is 1255871586.

It is not a de Polignac number, because 6851785521 - 2¹³ = 6851777329 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6851785531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1187910 + ... + 1193663.

It is an arithmetic number, because the mean of its divisors is an integer number (657314424).

Almost surely, 2^6851785521 is an apocalyptic number.

It is an amenable number.

6851785521 is a deficient number, since it is larger than the sum of its proper divisors (3665245263).

6851785521 is a wasteful number, since it uses less digits than its factorization.

6851785521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2381720.

The product of its digits is 672000, while the sum is 48.

The square root of 6851785521 is about 82775.5128102508. The cubic root of 6851785521 is about 1899.3336094239. Note that the first 3 decimals are identical.

The spelling of 6851785521 in words is "six billion, eight hundred fifty-one million, seven hundred eighty-five thousand, five hundred twenty-one".