21442133 has 2 divisors, whose sum is σ = 21442134. Its totient is φ = 21442132.

The previous prime is 21442103. The next prime is 21442159. The reversal of 21442133 is 33124412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21003889 + 438244 = 4583^2 + 662^2 .

It is a cyclic number.

It is not a de Polignac number, because 21442133 - 2¹⁸ = 21179989 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21442103) 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, 10721066 + 10721067.

It is an arithmetic number, because the mean of its divisors is an integer number (10721067).

Almost surely, 2^21442133 is an apocalyptic number.

It is an amenable number.

21442133 is a deficient number, since it is larger than the sum of its proper divisors (1).

21442133 is an equidigital number, since it uses as much as digits as its factorization.

21442133 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 20.

The square root of 21442133 is about 4630.5650843067. The cubic root of 21442133 is about 277.8151947049.

Adding to 21442133 its reverse (33124412), we get a palindrome (54566545).

The spelling of 21442133 in words is "twenty-one million, four hundred forty-two thousand, one hundred thirty-three".