21424435 has 4 divisors (see below), whose sum is σ = 25709328. Its totient is φ = 17139544.

The previous prime is 21424421. The next prime is 21424439. The reversal of 21424435 is 53442412.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21424435 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21424439) 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 in 3 ways as a sum of consecutive naturals, for example, 2142439 + ... + 2142448.

It is an arithmetic number, because the mean of its divisors is an integer number (6427332).

Almost surely, 2^21424435 is an apocalyptic number.

21424435 is a deficient number, since it is larger than the sum of its proper divisors (4284893).

21424435 is an equidigital number, since it uses as much as digits as its factorization.

21424435 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4284892.

The product of its digits is 3840, while the sum is 25.

The square root of 21424435 is about 4628.6536919497. The cubic root of 21424435 is about 277.7387388989.

Adding to 21424435 its reverse (53442412), we get a palindrome (74866847).

It can be divided in two parts, 214 and 24435, that added together give a square (24649 = 157²).

The spelling of 21424435 in words is "twenty-one million, four hundred twenty-four thousand, four hundred thirty-five".