21033161 has 2 divisors, whose sum is σ = 21033162. Its totient is φ = 21033160.

The previous prime is 21033151. The next prime is 21033163. The reversal of 21033161 is 16133012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19855936 + 1177225 = 4456^2 + 1085^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21033161 is a prime.

Together with 21033163, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21033163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10516580 + 10516581.

It is an arithmetic number, because the mean of its divisors is an integer number (10516581).

Almost surely, 2^21033161 is an apocalyptic number.

It is an amenable number.

21033161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21033161 is an equidigital number, since it uses as much as digits as its factorization.

21033161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 21033161 is about 4586.1924294561. The cubic root of 21033161 is about 276.0375614006.

Adding to 21033161 its reverse (16133012), we get a palindrome (37166173).

The spelling of 21033161 in words is "twenty-one million, thirty-three thousand, one hundred sixty-one".