99999643 has 2 divisors, whose sum is σ = 99999644.
Its totient is φ = 99999642.
The previous prime is 99999623. The next prime is 99999677. The reversal of 99999643 is 34699999.
It is a weak prime.
It is an emirp because it is prime and its reverse (34699999) is a distict prime.
It is a cyclic number.
It is not a de Polignac number, because 99999643 - 25 = 99999611 is a prime.
It is a nialpdrome in base 10.
It is not a weakly prime, because it can be changed into another prime (99999623) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49999821 + 49999822.
It is an arithmetic number, because the mean of its divisors is an integer number (49999822).
Almost surely, 299999643 is an apocalyptic number.
99999643 is a deficient number, since it is larger than the sum of its proper divisors (1).
99999643 is an equidigital number, since it uses as much as digits as its factorization.
99999643 is an evil number, because the sum of its binary digits is even.
The product of its digits is 4251528, while the sum is 58.
The square root of 99999643 is about 9999.9821499841.
The cubic root of 99999643 is about 464.1583310115.
The spelling of 99999643 in words is "ninety-nine million, nine hundred ninety-nine thousand, six hundred forty-three".