678021 has 4 divisors (see below), whose sum is σ = 904032. Its totient is φ = 452012.

The previous prime is 677983. The next prime is 678023. The reversal of 678021 is 120876.

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 678021 - 2¹¹ = 675973 is a prime.

It is a D-number.

It is a junction number, because it is equal to n+sod(n) for n = 677982 and 678000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (678023) 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, 113001 + ... + 113006.

It is an arithmetic number, because the mean of its divisors is an integer number (226008).

2⁶⁷⁸⁰²¹ is an apocalyptic number.

It is an amenable number.

678021 is a deficient number, since it is larger than the sum of its proper divisors (226011).

678021 is a wasteful number, since it uses less digits than its factorization.

678021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226010.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 678021 is about 823.4203057977. The cubic root of 678021 is about 87.8512034360.

Adding to 678021 its reverse (120876), we get a palindrome (798897).

The spelling of 678021 in words is "six hundred seventy-eight thousand, twenty-one".