21433421 has 2 divisors, whose sum is σ = 21433422. Its totient is φ = 21433420.

The previous prime is 21433417. The next prime is 21433427. The reversal of 21433421 is 12433412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18232900 + 3200521 = 4270^2 + 1789^2 .

It is a cyclic number.

It is not a de Polignac number, because 21433421 - 2² = 21433417 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21433393 and 21433402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21433427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10716710 + 10716711.

It is an arithmetic number, because the mean of its divisors is an integer number (10716711).

Almost surely, 2^21433421 is an apocalyptic number.

It is an amenable number.

21433421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21433421 is an equidigital number, since it uses as much as digits as its factorization.

21433421 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 21433421 is about 4629.6242828117. The cubic root of 21433421 is about 277.7775639050. Note that the first 3 decimals are identical.

Adding to 21433421 its reverse (12433412), we get a palindrome (33866833).

Subtracting from 21433421 its reverse (12433412), we obtain a palindrome (9000009).

The spelling of 21433421 in words is "twenty-one million, four hundred thirty-three thousand, four hundred twenty-one".