33199981 has 2 divisors, whose sum is σ = 33199982. Its totient is φ = 33199980.

The previous prime is 33199979. The next prime is 33200023. The reversal of 33199981 is 18999133.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 32661225 + 538756 = 5715^2 + 734^2 .

It is an emirp because it is prime and its reverse (18999133) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 33199981 - 2¹ = 33199979 is a prime.

It is a super-2 number, since 2×33199981² = 2204477476800722, which contains 22 as substring.

Together with 33199979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (33199931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16599990 + 16599991.

It is an arithmetic number, because the mean of its divisors is an integer number (16599991).

Almost surely, 2^33199981 is an apocalyptic number.

It is an amenable number.

33199981 is a deficient number, since it is larger than the sum of its proper divisors (1).

33199981 is an equidigital number, since it uses as much as digits as its factorization.

33199981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 52488, while the sum is 43.

The square root of 33199981 is about 5761.9424676059. The cubic root of 33199981 is about 321.4000537474.

The spelling of 33199981 in words is "thirty-three million, one hundred ninety-nine thousand, nine hundred eighty-one".