21051211543 has 2 divisors, whose sum is σ = 21051211544. Its totient is φ = 21051211542.

The previous prime is 21051211507. The next prime is 21051211549. The reversal of 21051211543 is 34511215012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21051211543 - 2⁹ = 21051211031 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21051211549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525605771 + 10525605772.

It is an arithmetic number, because the mean of its divisors is an integer number (10525605772).

Almost surely, 2^21051211543 is an apocalyptic number.

21051211543 is a deficient number, since it is larger than the sum of its proper divisors (1).

21051211543 is an equidigital number, since it uses as much as digits as its factorization.

21051211543 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1200, while the sum is 25.

Adding to 21051211543 its reverse (34511215012), we get a palindrome (55562426555).

The spelling of 21051211543 in words is "twenty-one billion, fifty-one million, two hundred eleven thousand, five hundred forty-three".