391679 has 2 divisors, whose sum is σ = 391680. Its totient is φ = 391678.

The previous prime is 391661. The next prime is 391691. The reversal of 391679 is 976193.

It is a strong prime.

It is an emirp because it is prime and its reverse (976193) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 391679 - 2¹⁶ = 326143 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391619) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195839 + 195840.

It is an arithmetic number, because the mean of its divisors is an integer number (195840).

2³⁹¹⁶⁷⁹ is an apocalyptic number.

391679 is a deficient number, since it is larger than the sum of its proper divisors (1).

391679 is an equidigital number, since it uses as much as digits as its factorization.

391679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10206, while the sum is 35.

The square root of 391679 is about 625.8426319771. The cubic root of 391679 is about 73.1661319231.

The spelling of 391679 in words is "three hundred ninety-one thousand, six hundred seventy-nine".