6851661599 has 2 divisors, whose sum is σ = 6851661600. Its totient is φ = 6851661598.

The previous prime is 6851661569. The next prime is 6851661631. The reversal of 6851661599 is 9951661586.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6851661599 - 2³² = 2556694303 is a prime.

It is a super-2 number, since 2×6851661599² = 93890533334422473602, which contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6851661559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3425830799 + 3425830800.

It is an arithmetic number, because the mean of its divisors is an integer number (3425830800).

Almost surely, 2^6851661599 is an apocalyptic number.

6851661599 is a deficient number, since it is larger than the sum of its proper divisors (1).

6851661599 is an equidigital number, since it uses as much as digits as its factorization.

6851661599 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3499200, while the sum is 56.

The square root of 6851661599 is about 82774.7642642370. The cubic root of 6851661599 is about 1899.3221588495.

The spelling of 6851661599 in words is "six billion, eight hundred fifty-one million, six hundred sixty-one thousand, five hundred ninety-nine".