21869233 has 2 divisors, whose sum is σ = 21869234. Its totient is φ = 21869232.

The previous prime is 21869201. The next prime is 21869249. The reversal of 21869233 is 33296812.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19254544 + 2614689 = 4388^2 + 1617^2 .

It is a cyclic number.

It is not a de Polignac number, because 21869233 - 2⁵ = 21869201 is a prime.

It is not a weakly prime, because it can be changed into another prime (21869033) 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, 10934616 + 10934617.

It is an arithmetic number, because the mean of its divisors is an integer number (10934617).

Almost surely, 2^21869233 is an apocalyptic number.

It is an amenable number.

21869233 is a deficient number, since it is larger than the sum of its proper divisors (1).

21869233 is an equidigital number, since it uses as much as digits as its factorization.

21869233 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 34.

The square root of 21869233 is about 4676.4551745954. The cubic root of 21869233 is about 279.6476562969.

The spelling of 21869233 in words is "twenty-one million, eight hundred sixty-nine thousand, two hundred thirty-three".