199943999 has 2 divisors, whose sum is σ = 199944000. Its totient is φ = 199943998.

The previous prime is 199943993. The next prime is 199944061. The reversal of 199943999 is 999349991.

It is an a-pointer prime, because the next prime (199944061) can be obtained adding 199943999 to its sum of digits (62).

It is a weak prime.

It is an emirp because it is prime and its reverse (999349991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 199943999 - 2⁴ = 199943983 is a prime.

It is a super-2 number, since 2×199943999² = 79955205472224002, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199943993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99971999 + 99972000.

It is an arithmetic number, because the mean of its divisors is an integer number (99972000).

Almost surely, 2^199943999 is an apocalyptic number.

199943999 is a deficient number, since it is larger than the sum of its proper divisors (1).

199943999 is an equidigital number, since it uses as much as digits as its factorization.

199943999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6377292, while the sum is 62.

The square root of 199943999 is about 14140.1555507710. The cubic root of 199943999 is about 584.7489599082.

The spelling of 199943999 in words is "one hundred ninety-nine million, nine hundred forty-three thousand, nine hundred ninety-nine".