199975681 has 2 divisors, whose sum is σ = 199975682. Its totient is φ = 199975680.

The previous prime is 199975679. The next prime is 199975729. The reversal of 199975681 is 186579991.

199975681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 134931456 + 65044225 = 11616^2 + 8065^2 .

It is a cyclic number.

It is not a de Polignac number, because 199975681 - 2¹ = 199975679 is a prime.

It is a super-2 number, since 2×199975681² = 79980545982827522, which contains 22 as substring.

Together with 199975679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (199975621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99987840 + 99987841.

It is an arithmetic number, because the mean of its divisors is an integer number (99987841).

Almost surely, 2^199975681 is an apocalyptic number.

It is an amenable number.

199975681 is a deficient number, since it is larger than the sum of its proper divisors (1).

199975681 is an equidigital number, since it uses as much as digits as its factorization.

199975681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1224720, while the sum is 55.

The square root of 199975681 is about 14141.2757911017. The cubic root of 199975681 is about 584.7798436193.

The spelling of 199975681 in words is "one hundred ninety-nine million, nine hundred seventy-five thousand, six hundred eighty-one".