391693686838 has 16 divisors (see below), whose sum is σ = 618615138240. Its totient is φ = 185493688200.

The previous prime is 391693686833. The next prime is 391693686847. The reversal of 391693686838 is 838686396193.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391693686833) by changing a digit.

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, 1104348 + ... + 1415263.

It is an arithmetic number, because the mean of its divisors is an integer number (38663446140).

Almost surely, 2^391693686838 is an apocalyptic number.

391693686838 is a gapful number since it is divisible by the number (38) formed by its first and last digit.

391693686838 is a deficient number, since it is larger than the sum of its proper divisors (226921451402).

391693686838 is a wasteful number, since it uses less digits than its factorization.

391693686838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2523723.

The product of its digits is 241864704, while the sum is 70.

The spelling of 391693686838 in words is "three hundred ninety-one billion, six hundred ninety-three million, six hundred eighty-six thousand, eight hundred thirty-eight".