21421333 has 2 divisors, whose sum is σ = 21421334. Its totient is φ = 21421332.

The previous prime is 21421319. The next prime is 21421373. The reversal of 21421333 is 33312412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12552849 + 8868484 = 3543^2 + 2978^2 .

It is a cyclic number.

It is not a de Polignac number, because 21421333 - 2¹³ = 21413141 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21421333.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21421373) 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 as a sum of consecutive naturals, namely, 10710666 + 10710667.

It is an arithmetic number, because the mean of its divisors is an integer number (10710667).

Almost surely, 2^21421333 is an apocalyptic number.

It is an amenable number.

21421333 is a deficient number, since it is larger than the sum of its proper divisors (1).

21421333 is an equidigital number, since it uses as much as digits as its factorization.

21421333 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432, while the sum is 19.

The square root of 21421333 is about 4628.3185931826. The cubic root of 21421333 is about 277.7253338445.

Adding to 21421333 its reverse (33312412), we get a palindrome (54733745).

The spelling of 21421333 in words is "twenty-one million, four hundred twenty-one thousand, three hundred thirty-three".