199997761 has 2 divisors, whose sum is σ = 199997762.
Its totient is φ = 199997760.
The previous prime is 199997731. The next prime is 199997767. The reversal of 199997761 is 167799991.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 108680625 + 91317136 = 10425^2 + 9556^2
It is an emirp because it is prime and its reverse (167799991) is a distict prime.
It is a cyclic number.
It is not a de Polignac number, because 199997761 - 215 = 199964993 is a prime.
It is a junction number, because it is equal to n+sod(n) for n = 199997696 and 199997705.
It is not a weakly prime, because it can be changed into another prime (199997767) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99998880 + 99998881.
It is an arithmetic number, because the mean of its divisors is an integer number (99998881).
Almost surely, 2199997761 is an apocalyptic number.
It is an amenable number.
199997761 is a deficient number, since it is larger than the sum of its proper divisors (1).
199997761 is an equidigital number, since it uses as much as digits as its factorization.
199997761 is an evil number, because the sum of its binary digits is even.
The product of its digits is 1928934, while the sum is 58.
The square root of 199997761 is about 14142.0564629052.
The cubic root of 199997761 is about 584.8013653425.
The spelling of 199997761 in words is "one hundred ninety-nine million, nine hundred ninety-seven thousand, seven hundred sixty-one".