687565729 has 2 divisors, whose sum is σ = 687565730. Its totient is φ = 687565728.

The previous prime is 687565667. The next prime is 687565733. The reversal of 687565729 is 927565786.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 601966225 + 85599504 = 24535^2 + 9252^2 .

It is a cyclic number.

It is not a de Polignac number, because 687565729 - 2⁷ = 687565601 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 687565729.

It is not a weakly prime, because it can be changed into another prime (687565129) 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, 343782864 + 343782865.

It is an arithmetic number, because the mean of its divisors is an integer number (343782865).

Almost surely, 2^687565729 is an apocalyptic number.

It is an amenable number.

687565729 is a deficient number, since it is larger than the sum of its proper divisors (1).

687565729 is an equidigital number, since it uses as much as digits as its factorization.

687565729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6350400, while the sum is 55.

The square root of 687565729 is about 26221.4745771476. The cubic root of 687565729 is about 882.6152097553.

The spelling of 687565729 in words is "six hundred eighty-seven million, five hundred sixty-five thousand, seven hundred twenty-nine".