199787971 has 2 divisors, whose sum is σ = 199787972. Its totient is φ = 199787970.

The previous prime is 199787941. The next prime is 199787977. The reversal of 199787971 is 179787991.

199787971 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 199787971 - 2¹⁵ = 199755203 is a prime.

It is not a weakly prime, because it can be changed into another prime (199787977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99893985 + 99893986.

It is an arithmetic number, because the mean of its divisors is an integer number (99893986).

Almost surely, 2^199787971 is an apocalyptic number.

199787971 is a deficient number, since it is larger than the sum of its proper divisors (1).

199787971 is an equidigital number, since it uses as much as digits as its factorization.

199787971 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2000376, while the sum is 58.

The square root of 199787971 is about 14134.6372786853. The cubic root of 199787971 is about 584.5968157177.

The spelling of 199787971 in words is "one hundred ninety-nine million, seven hundred eighty-seven thousand, nine hundred seventy-one".