391997879828 has 12 divisors (see below), whose sum is σ = 686251991040. Its totient is φ = 195925882392.

The previous prime is 391997879747. The next prime is 391997879843. The reversal of 391997879828 is 828978799193.

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 3 ways as a sum of consecutive naturals, for example, 18252308 + ... + 18273771.

It is an arithmetic number, because the mean of its divisors is an integer number (57187665920).

Almost surely, 2^391997879828 is an apocalyptic number.

It is an amenable number.

391997879828 is a deficient number, since it is larger than the sum of its proper divisors (294254111212).

391997879828 is a wasteful number, since it uses less digits than its factorization.

391997879828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36528766 (or 36528764 counting only the distinct ones).

The product of its digits is 987614208, while the sum is 80.

The spelling of 391997879828 in words is "three hundred ninety-one billion, nine hundred ninety-seven million, eight hundred seventy-nine thousand, eight hundred twenty-eight".