679 has 4 divisors (see below), whose sum is σ = 784. Its totient is φ = 576.

The previous prime is 677. The next prime is 683. The reversal of 679 is 976.

679 = T_{2} + T_{3} + ... +
T_{15}.

679 = 8^{2} + 9^{2} + ... + 13^{2}.

It is a semiprime because it is the product of two primes.

It is a 6-Lehmer number, since φ(679) divides (679-1)^{6}.

It is a cyclic number.

It is not a de Polignac number, because 679 - 2^{1} = 677 is a prime.

It is a super-2 number, since 2×679^{2} = 922082, which contains 22 as substring.

679 is a lucky number.

It is a plaindrome in base 8, base 10, base 11 and base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (673) 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, 42 + ... + 55.

It is an arithmetic number, because the mean of its divisors is an integer number (196).

679 is a deficient number, since it is larger than the sum of its proper divisors (105).

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

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

The sum of its prime factors is 104.

The product of its digits is 378, while the sum is 22.

The square root of 679 is about 26.0576284416. The cubic root of 679 is about 8.7893466122.

It can be divided in two parts, 6 and 79, that multiplied together give a palindrome (474).

The spelling of 679 in words is "six hundred seventy-nine", and thus it is an aban number and an oban number.

• e-mail: info -at- numbersaplenty.com • Privacy notice • done in 0.103 sec. • engine limits •