618391 has 4 divisors (see below), whose sum is σ = 619992. Its totient is φ = 616792.

The previous prime is 618377. The next prime is 618407. The reversal of 618391 is 193816.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 618391 - 2⁹ = 617879 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (618301) 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, 180 + ... + 1126.

It is an arithmetic number, because the mean of its divisors is an integer number (154998).

2⁶¹⁸³⁹¹ is an apocalyptic number.

618391 is a deficient number, since it is larger than the sum of its proper divisors (1601).

618391 is an equidigital number, since it uses as much as digits as its factorization.

618391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1600.

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

The square root of 618391 is about 786.3784076385. The cubic root of 618391 is about 85.1963626328.

The spelling of 618391 in words is "six hundred eighteen thousand, three hundred ninety-one".