20333981 has 2 divisors, whose sum is σ = 20333982. Its totient is φ = 20333980.

The previous prime is 20333977. The next prime is 20333983. The reversal of 20333981 is 18933302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18748900 + 1585081 = 4330^2 + 1259^2 .

It is a cyclic number.

It is not a de Polignac number, because 20333981 - 2² = 20333977 is a prime.

It is a super-2 number, since 2×20333981² = 826941566616722, which contains 22 as substring.

Together with 20333983, 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 (20333983) 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, 10166990 + 10166991.

It is an arithmetic number, because the mean of its divisors is an integer number (10166991).

Almost surely, 2^20333981 is an apocalyptic number.

It is an amenable number.

20333981 is a deficient number, since it is larger than the sum of its proper divisors (1).

20333981 is an equidigital number, since it uses as much as digits as its factorization.

20333981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 20333981 is about 4509.3215675975. The cubic root of 20333981 is about 272.9443682569.

The spelling of 20333981 in words is "twenty million, three hundred thirty-three thousand, nine hundred eighty-one".