678521 has 8 divisors (see below), whose sum is σ = 725760. Its totient is φ = 632128.

The previous prime is 678499. The next prime is 678533. The reversal of 678521 is 125876.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-678521 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (678541) 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 7 ways as a sum of consecutive naturals, for example, 2720 + ... + 2958.

It is an arithmetic number, because the mean of its divisors is an integer number (90720).

2⁶⁷⁸⁵²¹ is an apocalyptic number.

It is an amenable number.

678521 is a deficient number, since it is larger than the sum of its proper divisors (47239).

678521 is a wasteful number, since it uses less digits than its factorization.

678521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423.

The product of its digits is 3360, while the sum is 29.

The square root of 678521 is about 823.7238614973. The cubic root of 678521 is about 87.8727931353.

The spelling of 678521 in words is "six hundred seventy-eight thousand, five hundred twenty-one".