678551 has 4 divisors (see below), whose sum is σ = 680472. Its totient is φ = 676632.

The previous prime is 678541. The next prime is 678553. The reversal of 678551 is 155876.

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 678551 - 2¹⁸ = 416407 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 (678553) 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, 260 + ... + 1193.

It is an arithmetic number, because the mean of its divisors is an integer number (170118).

2⁶⁷⁸⁵⁵¹ is an apocalyptic number.

678551 is a deficient number, since it is larger than the sum of its proper divisors (1921).

678551 is a wasteful number, since it uses less digits than its factorization.

678551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1920.

The product of its digits is 8400, while the sum is 32.

The square root of 678551 is about 823.7420712820. The cubic root of 678551 is about 87.8740881799.

The spelling of 678551 in words is "six hundred seventy-eight thousand, five hundred fifty-one".