21543552571 has 2 divisors, whose sum is σ = 21543552572. Its totient is φ = 21543552570.

The previous prime is 21543552533. The next prime is 21543552599. The reversal of 21543552571 is 17525534512.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21543552571 is a prime.

It is not a weakly prime, because it can be changed into another prime (21543552521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10771776285 + 10771776286.

It is an arithmetic number, because the mean of its divisors is an integer number (10771776286).

Almost surely, 2^21543552571 is an apocalyptic number.

21543552571 is a deficient number, since it is larger than the sum of its proper divisors (1).

21543552571 is an equidigital number, since it uses as much as digits as its factorization.

21543552571 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 210000, while the sum is 40.

The spelling of 21543552571 in words is "twenty-one billion, five hundred forty-three million, five hundred fifty-two thousand, five hundred seventy-one".