21420333 has 24 divisors (see below), whose sum is σ = 34316256. Its totient is φ = 12765600.

The previous prime is 21420331. The next prime is 21420397. The reversal of 21420333 is 33302412.

It is not a de Polignac number, because 21420333 - 2¹ = 21420331 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21420331) 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 23 ways as a sum of consecutive naturals, for example, 4266 + ... + 7812.

It is an arithmetic number, because the mean of its divisors is an integer number (1429844).

Almost surely, 2^21420333 is an apocalyptic number.

It is an amenable number.

21420333 is a deficient number, since it is larger than the sum of its proper divisors (12895923).

21420333 is a wasteful number, since it uses less digits than its factorization.

21420333 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3625 (or 3622 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 18.

The square root of 21420333 is about 4628.2105613293. The cubic root of 21420333 is about 277.7210121456.

Adding to 21420333 its reverse (33302412), we get a palindrome (54722745).

The spelling of 21420333 in words is "twenty-one million, four hundred twenty thousand, three hundred thirty-three".