6878386661 has 4 divisors (see below), whose sum is σ = 6879088524. Its totient is φ = 6877684800.

The previous prime is 6878386651. The next prime is 6878386787. The reversal of 6878386661 is 1666838786.

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 1235522500 + 5642864161 = 35150^2 + 75119^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6878386661 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6878386661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6878386651) 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, 336020 + ... + 355901.

It is an arithmetic number, because the mean of its divisors is an integer number (1719772131).

Almost surely, 2^6878386661 is an apocalyptic number.

It is an amenable number.

6878386661 is a deficient number, since it is larger than the sum of its proper divisors (701863).

6878386661 is an equidigital number, since it uses as much as digits as its factorization.

6878386661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 701862.

The product of its digits is 13934592, while the sum is 59.

The square root of 6878386661 is about 82936.0395787019. The cubic root of 6878386661 is about 1901.7884048427.

The spelling of 6878386661 in words is "six billion, eight hundred seventy-eight million, three hundred eighty-six thousand, six hundred sixty-one".