999843421 has 2 divisors, whose sum is σ = 999843422.
Its totient is φ = 999843420.
The previous prime is 999843413. The next prime is 999843437. The reversal of 999843421 is 124348999.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 989794521 + 10048900 = 31461^2 + 3170^2
It is a cyclic number.
It is not a de Polignac number, because 999843421 - 23 = 999843413 is a prime.
It is equal to p50839969 and since 999843421 and 50839969 have the same sum of digits, it is a Honaker prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (999843521) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (17) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499921710 + 499921711.
It is an arithmetic number, because the mean of its divisors is an integer number (499921711).
Almost surely, 2999843421 is an apocalyptic number.
It is an amenable number.
999843421 is a deficient number, since it is larger than the sum of its proper divisors (1).
999843421 is an equidigital number, since it uses as much as digits as its factorization.
999843421 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 559872, while the sum is 49.
The square root of 999843421 is about 31620.3007733956.
The cubic root of 999843421 is about 999.9478042757.
The spelling of 999843421 in words is "nine hundred ninety-nine million, eight hundred forty-three thousand, four hundred twenty-one".