21275543 has 2 divisors, whose sum is σ = 21275544. Its totient is φ = 21275542.

The previous prime is 21275533. The next prime is 21275557. The reversal of 21275543 is 34557212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21275543 - 2¹⁴ = 21259159 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21275503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10637771 + 10637772.

It is an arithmetic number, because the mean of its divisors is an integer number (10637772).

Almost surely, 2^21275543 is an apocalyptic number.

21275543 is a deficient number, since it is larger than the sum of its proper divisors (1).

21275543 is an equidigital number, since it uses as much as digits as its factorization.

21275543 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8400, while the sum is 29.

The square root of 21275543 is about 4612.5419239287. The cubic root of 21275543 is about 277.0938483934.

The spelling of 21275543 in words is "twenty-one million, two hundred seventy-five thousand, five hundred forty-three".