1999979 has 2 divisors, whose sum is σ = 1999980. Its totient is φ = 1999978.

The previous prime is 1999969. The next prime is 1999993. The reversal of 1999979 is 9799991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1999979 - 2¹² = 1995883 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1999979.

It is not a weakly prime, because it can be changed into another prime (1999969) 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, 999989 + 999990.

It is an arithmetic number, because the mean of its divisors is an integer number (999990).

2^1999979 is an apocalyptic number.

1999979 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999979 is an equidigital number, since it uses as much as digits as its factorization.

1999979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 413343, while the sum is 53.

The square root of 1999979 is about 1414.2061377324. The cubic root of 1999979 is about 125.9916640156.

The spelling of 1999979 in words is "one million, nine hundred ninety-nine thousand, nine hundred seventy-nine".