6851645 has 4 divisors (see below), whose sum is σ = 8221980. Its totient is φ = 5481312.

The previous prime is 6851639. The next prime is 6851653. The reversal of 6851645 is 5461586.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1267876 + 5583769 = 1126^2 + 2363^2 .

It is a cyclic number.

It is not a de Polignac number, because 6851645 - 2¹⁴ = 6835261 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 685160 + ... + 685169.

It is an arithmetic number, because the mean of its divisors is an integer number (2055495).

Almost surely, 2^6851645 is an apocalyptic number.

It is an amenable number.

6851645 is a deficient number, since it is larger than the sum of its proper divisors (1370335).

6851645 is a wasteful number, since it uses less digits than its factorization.

6851645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1370334.

The product of its digits is 28800, while the sum is 35.

The square root of 6851645 is about 2617.5647078917. The cubic root of 6851645 is about 189.9320625067.

The spelling of 6851645 in words is "six million, eight hundred fifty-one thousand, six hundred forty-five".