199996981 has 2 divisors, whose sum is σ = 199996982. Its totient is φ = 199996980.

The previous prime is 199996967. The next prime is 199996987. The reversal of 199996981 is 189699991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 163200625 + 36796356 = 12775^2 + 6066^2 .

It is a cyclic number.

It is not a de Polignac number, because 199996981 - 2²¹ = 197899829 is a prime.

It is a super-2 number, since 2×199996981² = 79997584818228722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199996987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99998490 + 99998491.

It is an arithmetic number, because the mean of its divisors is an integer number (99998491).

Almost surely, 2^199996981 is an apocalyptic number.

It is an amenable number.

199996981 is a deficient number, since it is larger than the sum of its proper divisors (1).

199996981 is an equidigital number, since it uses as much as digits as its factorization.

199996981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2834352, while the sum is 61.

The square root of 199996981 is about 14142.0288855595. The cubic root of 199996981 is about 584.8006050913.

The spelling of 199996981 in words is "one hundred ninety-nine million, nine hundred ninety-six thousand, nine hundred eighty-one".