21310043 has 2 divisors, whose sum is σ = 21310044. Its totient is φ = 21310042.

The previous prime is 21310021. The next prime is 21310049. The reversal of 21310043 is 34001312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21310043 - 2⁸ = 21309787 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21310049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655021 + 10655022.

It is an arithmetic number, because the mean of its divisors is an integer number (10655022).

Almost surely, 2^21310043 is an apocalyptic number.

21310043 is a deficient number, since it is larger than the sum of its proper divisors (1).

21310043 is an equidigital number, since it uses as much as digits as its factorization.

21310043 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21310043 is about 4616.2802124654. The cubic root of 21310043 is about 277.2435441438.

Adding to 21310043 its reverse (34001312), we get a palindrome (55311355).

The spelling of 21310043 in words is "twenty-one million, three hundred ten thousand, forty-three".