21324451 has 2 divisors, whose sum is σ = 21324452. Its totient is φ = 21324450.

The previous prime is 21324421. The next prime is 21324463. The reversal of 21324451 is 15442312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21324451 - 2⁵ = 21324419 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21324421) 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, 10662225 + 10662226.

It is an arithmetic number, because the mean of its divisors is an integer number (10662226).

Almost surely, 2^21324451 is an apocalyptic number.

21324451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21324451 is an equidigital number, since it uses as much as digits as its factorization.

21324451 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 960, while the sum is 22.

The square root of 21324451 is about 4617.8405126206. The cubic root of 21324451 is about 277.3060127347.

Adding to 21324451 its reverse (15442312), we get a palindrome (36766763).

The spelling of 21324451 in words is "twenty-one million, three hundred twenty-four thousand, four hundred fifty-one".