678121 has 4 divisors (see below), whose sum is σ = 687744. Its totient is φ = 668500.

The previous prime is 678103. The next prime is 678133. The reversal of 678121 is 121876.

678121 is digitally balanced in base 2, 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 678121 - 2¹⁵ = 645353 is a prime.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (678101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4705 + ... + 4846.

It is an arithmetic number, because the mean of its divisors is an integer number (171936).

2⁶⁷⁸¹²¹ is an apocalyptic number.

It is an amenable number.

678121 is a deficient number, since it is larger than the sum of its proper divisors (9623).

678121 is an equidigital number, since it uses as much as digits as its factorization.

678121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9622.

The product of its digits is 672, while the sum is 25.

The square root of 678121 is about 823.4810258895. The cubic root of 678121 is about 87.8555222247.

Adding to 678121 its reverse (121876), we get a palindrome (799997).

The spelling of 678121 in words is "six hundred seventy-eight thousand, one hundred twenty-one".