199381681 has 2 divisors, whose sum is σ = 199381682. Its totient is φ = 199381680.

The previous prime is 199381643. The next prime is 199381691. The reversal of 199381681 is 186183991.

It is a happy number.

199381681 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 can be written as a sum of positive squares in only one way, i.e., 100180081 + 99201600 = 10009^2 + 9960^2 .

It is a cyclic number.

It is not a de Polignac number, because 199381681 - 2¹¹ = 199379633 is a prime.

It is a super-2 number, since 2×199381681² = 79506109436771522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (199381621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99690840 + 99690841.

It is an arithmetic number, because the mean of its divisors is an integer number (99690841).

Almost surely, 2^199381681 is an apocalyptic number.

It is an amenable number.

199381681 is a deficient number, since it is larger than the sum of its proper divisors (1).

199381681 is an equidigital number, since it uses as much as digits as its factorization.

199381681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 46.

The square root of 199381681 is about 14120.2578234252. The cubic root of 199381681 is about 584.2002669403.

The spelling of 199381681 in words is "one hundred ninety-nine million, three hundred eighty-one thousand, six hundred eighty-one".