21271043 has 2 divisors, whose sum is σ = 21271044. Its totient is φ = 21271042.

The previous prime is 21271039. The next prime is 21271057. The reversal of 21271043 is 34017212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21271043 - 2² = 21271039 is a prime.

It is not a weakly prime, because it can be changed into another prime (21271643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10635521 + 10635522.

It is an arithmetic number, because the mean of its divisors is an integer number (10635522).

Almost surely, 2^21271043 is an apocalyptic number.

21271043 is a deficient number, since it is larger than the sum of its proper divisors (1).

21271043 is an equidigital number, since it uses as much as digits as its factorization.

21271043 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 21271043 is about 4612.0540976879. The cubic root of 21271043 is about 277.0743109329.

Adding to 21271043 its reverse (34017212), we get a palindrome (55288255).

The spelling of 21271043 in words is "twenty-one million, two hundred seventy-one thousand, forty-three".