15691729 has 2 divisors, whose sum is σ = 15691730. Its totient is φ = 15691728.

The previous prime is 15691703. The next prime is 15691733. The reversal of 15691729 is 92719651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15421329 + 270400 = 3927^2 + 520^2 .

It is a cyclic number.

It is not a de Polignac number, because 15691729 - 2¹⁵ = 15658961 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 15691691 and 15691700.

It is not a weakly prime, because it can be changed into another prime (15691759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7845864 + 7845865.

It is an arithmetic number, because the mean of its divisors is an integer number (7845865).

Almost surely, 2^15691729 is an apocalyptic number.

It is an amenable number.

15691729 is a deficient number, since it is larger than the sum of its proper divisors (1).

15691729 is an equidigital number, since it uses as much as digits as its factorization.

15691729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34020, while the sum is 40.

The square root of 15691729 is about 3961.2787076902. The cubic root of 15691729 is about 250.3553825735.

The spelling of 15691729 in words is "fifteen million, six hundred ninety-one thousand, seven hundred twenty-nine".