391506 has 16 divisors (see below), whose sum is σ = 817344. Its totient is φ = 124784.

The previous prime is 391487. The next prime is 391519. The reversal of 391506 is 605193.

It is an unprimeable number.

391506 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1281 + ... + 1556.

It is an arithmetic number, because the mean of its divisors is an integer number (51084).

2³⁹¹⁵⁰⁶ is an apocalyptic number.

391506 is an abundant number, since it is smaller than the sum of its proper divisors (425838).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

391506 is a wasteful number, since it uses less digits than its factorization.

391506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2865.

The product of its (nonzero) digits is 810, while the sum is 24.

The square root of 391506 is about 625.7044030531. The cubic root of 391506 is about 73.1553581306.

Adding to 391506 its reverse (605193), we get a palindrome (996699).

The spelling of 391506 in words is "three hundred ninety-one thousand, five hundred six".