21424133 has 4 divisors (see below), whose sum is σ = 21587808. Its totient is φ = 21260460.

The previous prime is 21424129. The next prime is 21424159. The reversal of 21424133 is 33142412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21424133 - 2² = 21424129 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421133) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81641 + ... + 81902.

It is an arithmetic number, because the mean of its divisors is an integer number (5396952).

Almost surely, 2^21424133 is an apocalyptic number.

It is an amenable number.

21424133 is a deficient number, since it is larger than the sum of its proper divisors (163675).

21424133 is a wasteful number, since it uses less digits than its factorization.

21424133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163674.

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

The square root of 21424133 is about 4628.6210689578. The cubic root of 21424133 is about 277.7374338860.

Adding to 21424133 its reverse (33142412), we get a palindrome (54566545).

The spelling of 21424133 in words is "twenty-one million, four hundred twenty-four thousand, one hundred thirty-three".