6851369821 has 4 divisors (see below), whose sum is σ = 7018476444. Its totient is φ = 6684263200.

The previous prime is 6851369807. The next prime is 6851369827. The reversal of 6851369821 is 1289631586.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1289631586 = 2 ⋅644815793.

It can be written as a sum of positive squares in 2 ways, for example, as 3189425625 + 3661944196 = 56475^2 + 60514^2 .

It is a cyclic number.

It is not a de Polignac number, because 6851369821 - 2¹⁷ = 6851238749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6851369827) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 83553250 + ... + 83553331.

It is an arithmetic number, because the mean of its divisors is an integer number (1754619111).

Almost surely, 2^6851369821 is an apocalyptic number.

It is an amenable number.

6851369821 is a deficient number, since it is larger than the sum of its proper divisors (167106623).

6851369821 is a wasteful number, since it uses less digits than its factorization.

6851369821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167106622.

The product of its digits is 622080, while the sum is 49.

The square root of 6851369821 is about 82773.0017638602. The cubic root of 6851369821 is about 1899.2951975896.

The spelling of 6851369821 in words is "six billion, eight hundred fifty-one million, three hundred sixty-nine thousand, eight hundred twenty-one".