678491 has 4 divisors (see below), whose sum is σ = 740184. Its totient is φ = 616800.

The previous prime is 678481. The next prime is 678493. The reversal of 678491 is 194876.

678491 = 165² + 166² + ... + 186².

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

It is a cyclic number.

It is not a de Polignac number, because 678491 - 2¹⁴ = 662107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (678493) 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 in 3 ways as a sum of consecutive naturals, for example, 30830 + ... + 30851.

It is an arithmetic number, because the mean of its divisors is an integer number (185046).

2⁶⁷⁸⁴⁹¹ is an apocalyptic number.

678491 is a deficient number, since it is larger than the sum of its proper divisors (61693).

678491 is a wasteful number, since it uses less digits than its factorization.

678491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61692.

The product of its digits is 12096, while the sum is 35.

The square root of 678491 is about 823.7056513100. The cubic root of 678491 is about 87.8714980525.

It can be divided in two parts, 67 and 8491, that added together give a palindrome (8558).

The spelling of 678491 in words is "six hundred seventy-eight thousand, four hundred ninety-one".