199996681 has 2 divisors, whose sum is σ = 199996682.
Its totient is φ = 199996680.
The previous prime is 199996639. The next prime is 199996697. The reversal of 199996681 is 186699991.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 188128656 + 11868025 = 13716^2 + 3445^2
It is an emirp because it is prime and its reverse (186699991) is a distict prime.
It is a cyclic number.
It is not a de Polignac number, because 199996681 - 29 = 199996169 is a prime.
It is a super-2 number, since 2×1999966812 = 79997344822031522, which contains 22 as substring.
It is not a weakly prime, because it can be changed into another prime (199996981) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99998340 + 99998341.
It is an arithmetic number, because the mean of its divisors is an integer number (99998341).
Almost surely, 2199996681 is an apocalyptic number.
It is an amenable number.
199996681 is a deficient number, since it is larger than the sum of its proper divisors (1).
199996681 is an equidigital number, since it uses as much as digits as its factorization.
199996681 is an evil number, because the sum of its binary digits is even.
The product of its digits is 1889568, while the sum is 58.
The square root of 199996681 is about 14142.0182788738.
The cubic root of 199996681 is about 584.8003126864.
The spelling of 199996681 in words is "one hundred ninety-nine million, nine hundred ninety-six thousand, six hundred eighty-one".