21043542427 has 2 divisors, whose sum is σ = 21043542428. Its totient is φ = 21043542426.

The previous prime is 21043542413. The next prime is 21043542437. The reversal of 21043542427 is 72424534012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21043542427 - 2¹¹ = 21043540379 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21043542392 and 21043542401.

It is not a weakly prime, because it can be changed into another prime (21043542437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10521771213 + 10521771214.

It is an arithmetic number, because the mean of its divisors is an integer number (10521771214).

Almost surely, 2^21043542427 is an apocalyptic number.

21043542427 is a deficient number, since it is larger than the sum of its proper divisors (1).

21043542427 is an equidigital number, since it uses as much as digits as its factorization.

21043542427 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 53760, while the sum is 34.

The spelling of 21043542427 in words is "twenty-one billion, forty-three million, five hundred forty-two thousand, four hundred twenty-seven".