6421995686 has 16 divisors (see below), whose sum is σ = 9752387904. Its totient is φ = 3171226344.

The previous prime is 6421995673. The next prime is 6421995721. The reversal of 6421995686 is 6865991246.

It is a super-2 number, since 2×6421995686² = 82484057182005221192, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 719825 + ... + 728691.

It is an arithmetic number, because the mean of its divisors is an integer number (609524244).

Almost surely, 2^6421995686 is an apocalyptic number.

6421995686 is a deficient number, since it is larger than the sum of its proper divisors (3330392218).

6421995686 is a wasteful number, since it uses less digits than its factorization.

6421995686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13315.

The product of its digits is 5598720, while the sum is 56.

The square root of 6421995686 is about 80137.3551223148. The cubic root of 6421995686 is about 1858.7600791222.

The spelling of 6421995686 in words is "six billion, four hundred twenty-one million, nine hundred ninety-five thousand, six hundred eighty-six".