21233081 has 2 divisors, whose sum is σ = 21233082. Its totient is φ = 21233080.

The previous prime is 21233059. The next prime is 21233087. The reversal of 21233081 is 18033212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17935225 + 3297856 = 4235^2 + 1816^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21233081 is a prime.

It is a super-2 number, since 2×21233081² = 901687457505122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21233087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10616540 + 10616541.

It is an arithmetic number, because the mean of its divisors is an integer number (10616541).

Almost surely, 2^21233081 is an apocalyptic number.

It is an amenable number.

21233081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21233081 is an equidigital number, since it uses as much as digits as its factorization.

21233081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 21233081 is about 4607.9367400172. The cubic root of 21233081 is about 276.9093831409.

Adding to 21233081 its reverse (18033212), we get a palindrome (39266293).

The spelling of 21233081 in words is "twenty-one million, two hundred thirty-three thousand, eighty-one".