679921 has 8 divisors (see below), whose sum is σ = 749664. Its totient is φ = 611520.

The previous prime is 679919. The next prime is 679933. The reversal of 679921 is 129976.

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

It is a cyclic number.

It is not a de Polignac number, because 679921 - 2¹ = 679919 is a prime.

It is a Duffinian number.

679921 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (679951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 970 + ... + 1516.

It is an arithmetic number, because the mean of its divisors is an integer number (93708).

2⁶⁷⁹⁹²¹ is an apocalyptic number.

It is an amenable number.

679921 is a deficient number, since it is larger than the sum of its proper divisors (69743).

679921 is a wasteful number, since it uses less digits than its factorization.

679921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 671.

The product of its digits is 6804, while the sum is 34.

The square root of 679921 is about 824.5732229463. The cubic root of 679921 is about 87.9331879236.

Subtracting from 679921 its reverse (129976), we obtain a palindrome (549945).

It can be divided in two parts, 679 and 921, that added together give a square (1600 = 40²).

The spelling of 679921 in words is "six hundred seventy-nine thousand, nine hundred twenty-one".