999821279 has 2 divisors, whose sum is σ = 999821280. Its totient is φ = 999821278.

The previous prime is 999821261. The next prime is 999821297. The reversal of 999821279 is 972128999.

It is a happy number.

Together with next prime (999821297) it forms an Ormiston pair, because they use the same digits, order apart.

It is a balanced prime because it is at equal distance from previous prime (999821261) and next prime (999821297).

It is an emirp because it is prime and its reverse (972128999) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-999821279 is a 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 (999821239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499910639 + 499910640.

It is an arithmetic number, because the mean of its divisors is an integer number (499910640).

Almost surely, 2^999821279 is an apocalyptic number.

999821279 is a deficient number, since it is larger than the sum of its proper divisors (1).

999821279 is an equidigital number, since it uses as much as digits as its factorization.

999821279 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1469664, while the sum is 56.

The square root of 999821279 is about 31619.9506482853. The cubic root of 999821279 is about 999.9404227840.

The spelling of 999821279 in words is "nine hundred ninety-nine million, eight hundred twenty-one thousand, two hundred seventy-nine".