21030043 has 2 divisors, whose sum is σ = 21030044. Its totient is φ = 21030042.

The previous prime is 21030001. The next prime is 21030047. The reversal of 21030043 is 34003012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21030043 - 2¹³ = 21021851 is a prime.

It is not a weakly prime, because it can be changed into another prime (21030047) 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 as a sum of consecutive naturals, namely, 10515021 + 10515022.

It is an arithmetic number, because the mean of its divisors is an integer number (10515022).

Almost surely, 2^21030043 is an apocalyptic number.

21030043 is a deficient number, since it is larger than the sum of its proper divisors (1).

21030043 is an equidigital number, since it uses as much as digits as its factorization.

21030043 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 21030043 is about 4585.8524834539. The cubic root of 21030043 is about 276.0239205971.

Adding to 21030043 its reverse (34003012), we get a palindrome (55033055).

The spelling of 21030043 in words is "twenty-one million, thirty thousand, forty-three".