11615881729 has 3 divisors (see below), whose sum is σ = 11615989507. Its totient is φ = 11615773952.

The previous prime is 11615881727. The next prime is 11615881741. The reversal of 11615881729 is 92718851611.

The square root of 11615881729 is 107777.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 92718851611 = 56807 ⋅1632173.

It can be written as a sum of positive squares in only one way, i.e., 8452044225 + 3163837504 = 91935^2 + 56248^2 .

It is not a de Polignac number, because 11615881729 - 2¹ = 11615881727 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11615881721) 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 in 2 ways as a sum of consecutive naturals, for example, 53889 + ... + 161665.

Almost surely, 2^11615881729 is an apocalyptic number.

11615881729 is the 107777-th square number.

11615881729 is the 53889-th centered octagonal number.

It is an amenable number.

11615881729 is a deficient number, since it is larger than the sum of its proper divisors (107778).

11615881729 is an frugal number, since it uses more digits than its factorization.

11615881729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215554 (or 107777 counting only the distinct ones).

The product of its digits is 241920, while the sum is 49.

Multiplying 11615881729 by its sum of digits (49), we get a square (569178204721 = 754439²).

The spelling of 11615881729 in words is "eleven billion, six hundred fifteen million, eight hundred eighty-one thousand, seven hundred twenty-nine".