33821981 has 2 divisors, whose sum is σ = 33821982. Its totient is φ = 33821980.

The previous prime is 33821969. The next prime is 33821987. The reversal of 33821981 is 18912833.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 33235225 + 586756 = 5765^2 + 766^2 .

It is a cyclic number.

It is not a de Polignac number, because 33821981 - 2¹⁸ = 33559837 is a prime.

It is a super-2 number, since 2×33821981² = 2287852797528722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (33821987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16910990 + 16910991.

It is an arithmetic number, because the mean of its divisors is an integer number (16910991).

Almost surely, 2^33821981 is an apocalyptic number.

It is an amenable number.

33821981 is a deficient number, since it is larger than the sum of its proper divisors (1).

33821981 is an equidigital number, since it uses as much as digits as its factorization.

33821981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 35.

The square root of 33821981 is about 5815.6668577215. Note that the first 3 decimals coincide. The cubic root of 33821981 is about 323.3947860900.

The spelling of 33821981 in words is "thirty-three million, eight hundred twenty-one thousand, nine hundred eighty-one".