391081 has 4 divisors (see below), whose sum is σ = 392832. Its totient is φ = 389332.

The previous prime is 391073. The next prime is 391103. The reversal of 391081 is 180193.

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.

It is a cyclic number.

It is not a de Polignac number, because 391081 - 2³ = 391073 is a prime.

It is a super-2 number, since 2×391081² = 305888697122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391021) 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, 481 + ... + 1006.

It is an arithmetic number, because the mean of its divisors is an integer number (98208).

2³⁹¹⁰⁸¹ is an apocalyptic number.

It is an amenable number.

391081 is a deficient number, since it is larger than the sum of its proper divisors (1751).

391081 is a wasteful number, since it uses less digits than its factorization.

391081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1750.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 391081 is about 625.3646935989. The cubic root of 391081 is about 73.1288772386.

The spelling of 391081 in words is "three hundred ninety-one thousand, eighty-one".