33619981 has 2 divisors, whose sum is σ = 33619982. Its totient is φ = 33619980.

The previous prime is 33619979. The next prime is 33620003. The reversal of 33619981 is 18991633.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19624900 + 13995081 = 4430^2 + 3741^2 .

It is an emirp because it is prime and its reverse (18991633) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 33619981 - 2¹ = 33619979 is a prime.

It is a super-2 number, since 2×33619981² = 2260606244880722, which contains 22 as substring.

Together with 33619979, 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 (33619681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16809990 + 16809991.

It is an arithmetic number, because the mean of its divisors is an integer number (16809991).

Almost surely, 2^33619981 is an apocalyptic number.

It is an amenable number.

33619981 is a deficient number, since it is larger than the sum of its proper divisors (1).

33619981 is an equidigital number, since it uses as much as digits as its factorization.

33619981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34992, while the sum is 40.

The square root of 33619981 is about 5798.2739673113. The cubic root of 33619981 is about 322.7496806524.

The spelling of 33619981 in words is "thirty-three million, six hundred nineteen thousand, nine hundred eighty-one".