21420033 has 4 divisors (see below), whose sum is σ = 28560048. Its totient is φ = 14280020.

The previous prime is 21420031. The next prime is 21420037. The reversal of 21420033 is 33002412.

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 21420033 - 2¹ = 21420031 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21419994 and 21420021.

It is not an unprimeable number, because it can be changed into a prime (21420031) 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, 3570003 + ... + 3570008.

It is an arithmetic number, because the mean of its divisors is an integer number (7140012).

Almost surely, 2^21420033 is an apocalyptic number.

It is an amenable number.

21420033 is a deficient number, since it is larger than the sum of its proper divisors (7140015).

21420033 is an equidigital number, since it uses as much as digits as its factorization.

21420033 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7140014.

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 21420033 is about 4628.1781512816. The cubic root of 21420033 is about 277.7197156097.

Adding to 21420033 its reverse (33002412), we get a palindrome (54422445).

The spelling of 21420033 in words is "twenty-one million, four hundred twenty thousand, thirty-three".