391618 has 4 divisors (see below), whose sum is σ = 587430. Its totient is φ = 195808.

The previous prime is 391613. The next prime is 391619. The reversal of 391618 is 816193.

It is a happy number.

391618 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 237169 + 154449 = 487^2 + 393^2 .

It is not an unprimeable number, because it can be changed into a prime (391613) by changing a digit.

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 as a sum of consecutive naturals, namely, 97903 + ... + 97906.

2³⁹¹⁶¹⁸ is an apocalyptic number.

391618 is a deficient number, since it is larger than the sum of its proper divisors (195812).

391618 is a wasteful number, since it uses less digits than its factorization.

391618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195811.

The product of its digits is 1296, while the sum is 28.

The square root of 391618 is about 625.7938957836. The cubic root of 391618 is about 73.1623334336.

The spelling of 391618 in words is "three hundred ninety-one thousand, six hundred eighteen".