203819981 has 2 divisors, whose sum is σ = 203819982. Its totient is φ = 203819980.

The previous prime is 203819977. The next prime is 203819983. The reversal of 203819981 is 189918302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 200788900 + 3031081 = 14170^2 + 1741^2 .

It is a cyclic number.

It is not a de Polignac number, because 203819981 - 2² = 203819977 is a prime.

It is a super-2 number, since 2×203819981² = 83085169309680722, which contains 22 as substring.

Together with 203819983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (203819983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 101909990 + 101909991.

It is an arithmetic number, because the mean of its divisors is an integer number (101909991).

Almost surely, 2^203819981 is an apocalyptic number.

It is an amenable number.

203819981 is a deficient number, since it is larger than the sum of its proper divisors (1).

203819981 is an equidigital number, since it uses as much as digits as its factorization.

203819981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 41.

The square root of 203819981 is about 14276.5535406834. The cubic root of 203819981 is about 588.5033222967.

The spelling of 203819981 in words is "two hundred three million, eight hundred nineteen thousand, nine hundred eighty-one".