11543563721 has 2 divisors, whose sum is σ = 11543563722. Its totient is φ = 11543563720.

The previous prime is 11543563687. The next prime is 11543563729. The reversal of 11543563721 is 12736534511.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11405172025 + 138391696 = 106795^2 + 11764^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11543563721 is a prime.

It is not a weakly prime, because it can be changed into another prime (11543563729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5771781860 + 5771781861.

It is an arithmetic number, because the mean of its divisors is an integer number (5771781861).

Almost surely, 2^11543563721 is an apocalyptic number.

It is an amenable number.

11543563721 is a deficient number, since it is larger than the sum of its proper divisors (1).

11543563721 is an equidigital number, since it uses as much as digits as its factorization.

11543563721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 75600, while the sum is 38.

The spelling of 11543563721 in words is "eleven billion, five hundred forty-three million, five hundred sixty-three thousand, seven hundred twenty-one".