11915473721 has 2 divisors, whose sum is σ = 11915473722. Its totient is φ = 11915473720.

The previous prime is 11915473693. The next prime is 11915473729. The reversal of 11915473721 is 12737451911.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6199357696 + 5716116025 = 78736^2 + 75605^2 .

It is a cyclic number.

It is not a de Polignac number, because 11915473721 - 2⁶ = 11915473657 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (11915473729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5957736860 + 5957736861.

It is an arithmetic number, because the mean of its divisors is an integer number (5957736861).

Almost surely, 2^11915473721 is an apocalyptic number.

It is an amenable number.

11915473721 is a deficient number, since it is larger than the sum of its proper divisors (1).

11915473721 is an equidigital number, since it uses as much as digits as its factorization.

11915473721 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 11915473721 in words is "eleven billion, nine hundred fifteen million, four hundred seventy-three thousand, seven hundred twenty-one".