21021343 has 6 divisors (see below), whose sum is σ = 24453456. Its totient is φ = 18018252.

The previous prime is 21021331. The next prime is 21021349. The reversal of 21021343 is 34312012.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-21021343 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021349) 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 in 5 ways as a sum of consecutive naturals, for example, 214455 + ... + 214552.

It is an arithmetic number, because the mean of its divisors is an integer number (4075576).

Almost surely, 2^21021343 is an apocalyptic number.

21021343 is a deficient number, since it is larger than the sum of its proper divisors (3432113).

21021343 is an equidigital number, since it uses as much as digits as its factorization.

21021343 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 429021 (or 429014 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21021343 is about 4584.9038157850. The cubic root of 21021343 is about 275.9858522119.

Adding to 21021343 its reverse (34312012), we get a palindrome (55333355).

The spelling of 21021343 in words is "twenty-one million, twenty-one thousand, three hundred forty-three".