391066 has 16 divisors (see below), whose sum is σ = 642600. Its totient is φ = 178464.

The previous prime is 391063. The next prime is 391067. The reversal of 391066 is 660193.

It can be written as a sum of positive squares in 4 ways, for example, as 441 + 390625 = 21^2 + 625^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 391066.

It is not an unprimeable number, because it can be changed into a prime (391063) 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 7 ways as a sum of consecutive naturals, for example, 4350 + ... + 4438.

2³⁹¹⁰⁶⁶ is an apocalyptic number.

391066 is a deficient number, since it is larger than the sum of its proper divisors (251534).

391066 is an equidigital number, since it uses as much as digits as its factorization.

391066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130 (or 104 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 25.

The square root of 391066 is about 625.3527004819. The cubic root of 391066 is about 73.1279422684.

The spelling of 391066 in words is "three hundred ninety-one thousand, sixty-six".