6391899989 has 12 divisors (see below), whose sum is σ = 6866331300. Its totient is φ = 5948287488.

The previous prime is 6391899931. The next prime is 6391900001. The reversal of 6391899989 is 9899981936.

It can be written as a sum of positive squares in 6 ways, for example, as 223054225 + 6168845764 = 14935^2 + 78542^2 .

It is not a de Polignac number, because 6391899989 - 2¹² = 6391895893 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 (6391899919) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 98534 + ... + 149975.

It is an arithmetic number, because the mean of its divisors is an integer number (572194275).

Almost surely, 2^6391899989 is an apocalyptic number.

It is an amenable number.

6391899989 is a deficient number, since it is larger than the sum of its proper divisors (474431311).

6391899989 is a wasteful number, since it uses less digits than its factorization.

6391899989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248632 (or 248615 counting only the distinct ones).

The product of its digits is 68024448, while the sum is 71.

The square root of 6391899989 is about 79949.3589029956. The cubic root of 6391899989 is about 1855.8519335911.

The spelling of 6391899989 in words is "six billion, three hundred ninety-one million, eight hundred ninety-nine thousand, nine hundred eighty-nine".