21240133 has 2 divisors, whose sum is σ = 21240134. Its totient is φ = 21240132.

The previous prime is 21240101. The next prime is 21240161. The reversal of 21240133 is 33104212.

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., 15000129 + 6240004 = 3873^2 + 2498^2 .

It is a cyclic number.

It is not a de Polignac number, because 21240133 - 2⁵ = 21240101 is a prime.

It is a super-2 number, since 2×21240133² = 902286499715378, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21240433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10620066 + 10620067.

It is an arithmetic number, because the mean of its divisors is an integer number (10620067).

Almost surely, 2^21240133 is an apocalyptic number.

It is an amenable number.

21240133 is a deficient number, since it is larger than the sum of its proper divisors (1).

21240133 is an equidigital number, since it uses as much as digits as its factorization.

21240133 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21240133 is about 4608.7018779695. The cubic root of 21240133 is about 276.9400357630.

Adding to 21240133 its reverse (33104212), we get a palindrome (54344345).

The spelling of 21240133 in words is "twenty-one million, two hundred forty thousand, one hundred thirty-three".