391886121 has 16 divisors (see below), whose sum is σ = 594800640. Its totient is φ = 227179920.

The previous prime is 391886087. The next prime is 391886197. The reversal of 391886121 is 121688193.

It is not a de Polignac number, because 391886121 - 2⁹ = 391885609 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 391886121.

It is not an unprimeable number, because it can be changed into a prime (391886321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 257401 + ... + 258918.

It is an arithmetic number, because the mean of its divisors is an integer number (37175040).

Almost surely, 2^391886121 is an apocalyptic number.

It is an amenable number.

391886121 is a deficient number, since it is larger than the sum of its proper divisors (202914519).

391886121 is a wasteful number, since it uses less digits than its factorization.

391886121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 516356.

The product of its digits is 20736, while the sum is 39.

The square root of 391886121 is about 19796.1137852862. The cubic root of 391886121 is about 731.7902647198.

The spelling of 391886121 in words is "three hundred ninety-one million, eight hundred eighty-six thousand, one hundred twenty-one".