79999 has 2 divisors, whose sum is σ = 80000. Its totient is φ = 79998.

The previous prime is 79997. The next prime is 80021. The reversal of 79999 is 99997.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 79999 - 2¹ = 79997 is a prime.

Together with 79997, it forms a pair of twin primes.

79999 is a modest number, since divided by 999 gives 79 as remainder.

It is a plaindrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79997) 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 as a sum of consecutive naturals, namely, 39999 + 40000.

It is an arithmetic number, because the mean of its divisors is an integer number (40000).

2⁷⁹⁹⁹⁹ is an apocalyptic number.

79999 is a deficient number, since it is larger than the sum of its proper divisors (1).

79999 is an equidigital number, since it uses as much as digits as its factorization.

79999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45927, while the sum is 43.

The square root of 79999 is about 282.8409447021. The cubic root of 79999 is about 43.0885142637.

It can be divided in two parts, 7999 and 9, that added together give a palindrome (8008).

The spelling of 79999 in words is "seventy-nine thousand, nine hundred ninety-nine".