199055981 has 2 divisors, whose sum is σ = 199055982. Its totient is φ = 199055980.

The previous prime is 199055977. The next prime is 199056019. The reversal of 199055981 is 189550991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 186868900 + 12187081 = 13670^2 + 3491^2 .

It is a cyclic number.

It is not a de Polignac number, because 199055981 - 2² = 199055977 is a prime.

It is a super-2 number, since 2×199055981² = 79246567143744722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199055081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99527990 + 99527991.

It is an arithmetic number, because the mean of its divisors is an integer number (99527991).

Almost surely, 2^199055981 is an apocalyptic number.

It is an amenable number.

199055981 is a deficient number, since it is larger than the sum of its proper divisors (1).

199055981 is an equidigital number, since it uses as much as digits as its factorization.

199055981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145800, while the sum is 47.

The square root of 199055981 is about 14108.7200340782. The cubic root of 199055981 is about 583.8819867327.

The spelling of 199055981 in words is "one hundred ninety-nine million, fifty-five thousand, nine hundred eighty-one".