999666431 has 2 divisors, whose sum is σ = 999666432.
Its totient is φ = 999666430.
The previous prime is 999666413. The next prime is 999666461. The reversal of 999666431 is 134666999.
Together with previous prime (999666413) it forms an Ormiston pair, because they use the same digits, order apart.
It is a weak prime.
It is an emirp because it is prime and its reverse (134666999) is a distict prime.
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-999666431 is a prime.
It is a super-2 number, since 2×9996664312 = 1998665946536555522, which contains 22 as substring.
It is a Chen prime.
It is a nialpdrome in base 10.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (999666461) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499833215 + 499833216.
It is an arithmetic number, because the mean of its divisors is an integer number (499833216).
Almost surely, 2999666431 is an apocalyptic number.
999666431 is a deficient number, since it is larger than the sum of its proper divisors (1).
999666431 is an equidigital number, since it uses as much as digits as its factorization.
999666431 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 1889568, while the sum is 53.
The square root of 999666431 is about 31617.5019727998.
The cubic root of 999666431 is about 999.8887979679.
Note that the first 3 decimals are identical.
The spelling of 999666431 in words is "nine hundred ninety-nine million, six hundred sixty-six thousand, four hundred thirty-one".