199145981 has 2 divisors, whose sum is σ = 199145982. Its totient is φ = 199145980.

The previous prime is 199145911. The next prime is 199145993. The reversal of 199145981 is 189541991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 147233956 + 51912025 = 12134^2 + 7205^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-199145981 is a prime.

It is a super-3 number, since 3×199145981³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199145911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99572990 + 99572991.

It is an arithmetic number, because the mean of its divisors is an integer number (99572991).

Almost surely, 2^199145981 is an apocalyptic number.

It is an amenable number.

199145981 is a deficient number, since it is larger than the sum of its proper divisors (1).

199145981 is an equidigital number, since it uses as much as digits as its factorization.

199145981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 116640, while the sum is 47.

The square root of 199145981 is about 14111.9091904675. The cubic root of 199145981 is about 583.9699711291.

The spelling of 199145981 in words is "one hundred ninety-nine million, one hundred forty-five thousand, nine hundred eighty-one".