820979 has 4 divisors (see below), whose sum is σ = 823584. Its totient is φ = 818376.

The previous prime is 820969. The next prime is 820991. The reversal of 820979 is 979028.

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

It is a cyclic number.

It is not a de Polignac number, because 820979 - 2⁸ = 820723 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (820909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 752 + ... + 1485.

It is an arithmetic number, because the mean of its divisors is an integer number (205896).

2⁸²⁰⁹⁷⁹ is an apocalyptic number.

820979 is a deficient number, since it is larger than the sum of its proper divisors (2605).

820979 is a wasteful number, since it uses less digits than its factorization.

820979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2604.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 820979 is about 906.0789148855. The cubic root of 820979 is about 93.6362507818.

The spelling of 820979 in words is "eight hundred twenty thousand, nine hundred seventy-nine".