11551721543 has 2 divisors, whose sum is σ = 11551721544. Its totient is φ = 11551721542.

The previous prime is 11551721509. The next prime is 11551721647. The reversal of 11551721543 is 34512715511.

It is a weak prime.

It is an emirp because it is prime and its reverse (34512715511) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11551721543 - 2¹⁴ = 11551705159 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11551721143) 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, 5775860771 + 5775860772.

It is an arithmetic number, because the mean of its divisors is an integer number (5775860772).

Almost surely, 2^11551721543 is an apocalyptic number.

11551721543 is a deficient number, since it is larger than the sum of its proper divisors (1).

11551721543 is an equidigital number, since it uses as much as digits as its factorization.

11551721543 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21000, while the sum is 35.

The spelling of 11551721543 in words is "eleven billion, five hundred fifty-one million, seven hundred twenty-one thousand, five hundred forty-three".