391121 has 4 divisors (see below), whose sum is σ = 393072. Its totient is φ = 389172.

The previous prime is 391117. The next prime is 391133. The reversal of 391121 is 121193.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 121193 = 17 ⋅7129.

It is a cyclic number.

It is not a de Polignac number, because 391121 - 2² = 391117 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 391121.

It is not an unprimeable number, because it can be changed into a prime (391151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 635 + ... + 1088.

It is an arithmetic number, because the mean of its divisors is an integer number (98268).

2³⁹¹¹²¹ is an apocalyptic number.

It is an amenable number.

391121 is a deficient number, since it is larger than the sum of its proper divisors (1951).

391121 is a wasteful number, since it uses less digits than its factorization.

391121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1950.

The product of its digits is 54, while the sum is 17.

The square root of 391121 is about 625.3966741197. The cubic root of 391121 is about 73.1313703755.

It can be divided in two parts, 391 and 121, that added together give a 9-th power (512 = 2⁹).

The spelling of 391121 in words is "three hundred ninety-one thousand, one hundred twenty-one".