11539471721 has 2 divisors, whose sum is σ = 11539471722. Its totient is φ = 11539471720.

The previous prime is 11539471663. The next prime is 11539471729. The reversal of 11539471721 is 12717493511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6828708496 + 4710763225 = 82636^2 + 68635^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11539471721 is a prime.

It is not a weakly prime, because it can be changed into another prime (11539471729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5769735860 + 5769735861.

It is an arithmetic number, because the mean of its divisors is an integer number (5769735861).

Almost surely, 2^11539471721 is an apocalyptic number.

It is an amenable number.

11539471721 is a deficient number, since it is larger than the sum of its proper divisors (1).

11539471721 is an equidigital number, since it uses as much as digits as its factorization.

11539471721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 52920, while the sum is 41.

The spelling of 11539471721 in words is "eleven billion, five hundred thirty-nine million, four hundred seventy-one thousand, seven hundred twenty-one".