21444233 has 2 divisors, whose sum is σ = 21444234. Its totient is φ = 21444232.

The previous prime is 21444223. The next prime is 21444239. The reversal of 21444233 is 33244412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18088009 + 3356224 = 4253^2 + 1832^2 .

It is a cyclic number.

It is not a de Polignac number, because 21444233 - 2¹² = 21440137 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21444199 and 21444208.

It is not a weakly prime, because it can be changed into another prime (21444239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10722116 + 10722117.

It is an arithmetic number, because the mean of its divisors is an integer number (10722117).

Almost surely, 2^21444233 is an apocalyptic number.

It is an amenable number.

21444233 is a deficient number, since it is larger than the sum of its proper divisors (1).

21444233 is an equidigital number, since it uses as much as digits as its factorization.

21444233 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 23.

The square root of 21444233 is about 4630.7918329374. The cubic root of 21444233 is about 277.8242639653.

Adding to 21444233 its reverse (33244412), we get a palindrome (54688645).

The spelling of 21444233 in words is "twenty-one million, four hundred forty-four thousand, two hundred thirty-three".