199729681 has 2 divisors, whose sum is σ = 199729682. Its totient is φ = 199729680.

The previous prime is 199729661. The next prime is 199729709. The reversal of 199729681 is 186927991.

199729681 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., 198810000 + 919681 = 14100^2 + 959^2 .

It is an emirp because it is prime and its reverse (186927991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 199729681 - 2⁹ = 199729169 is a prime.

It is a super-2 number, since 2×199729681² = 79783890944723522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (199729661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99864840 + 99864841.

It is an arithmetic number, because the mean of its divisors is an integer number (99864841).

Almost surely, 2^199729681 is an apocalyptic number.

It is an amenable number.

199729681 is a deficient number, since it is larger than the sum of its proper divisors (1).

199729681 is an equidigital number, since it uses as much as digits as its factorization.

199729681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 489888, while the sum is 52.

The square root of 199729681 is about 14132.5751722749. The cubic root of 199729681 is about 584.5399563337.

The spelling of 199729681 in words is "one hundred ninety-nine million, seven hundred twenty-nine thousand, six hundred eighty-one".