6391998 has 12 divisors (see below), whose sum is σ = 13849368. Its totient is φ = 2130660.

The previous prime is 6391991. The next prime is 6392003. The reversal of 6391998 is 8991936.

6391998 is a `hidden beast` number, since 639 + 1 + 9 + 9 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6391991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 177538 + ... + 177573.

It is an arithmetic number, because the mean of its divisors is an integer number (1154114).

Almost surely, 2^6391998 is an apocalyptic number.

6391998 is an abundant number, since it is smaller than the sum of its proper divisors (7457370).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6391998 is a wasteful number, since it uses less digits than its factorization.

6391998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355119 (or 355116 counting only the distinct ones).

The product of its digits is 104976, while the sum is 45.

The square root of 6391998 is about 2528.2400993577. The cubic root of 6391998 is about 185.5861419189.

The spelling of 6391998 in words is "six million, three hundred ninety-one thousand, nine hundred ninety-eight".