689765729 has 4 divisors (see below), whose sum is σ = 708408084. Its totient is φ = 671123376.

The previous prime is 689765723. The next prime is 689765743. The reversal of 689765729 is 927567986.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 254083600 + 435682129 = 15940^2 + 20873^2 .

It is a cyclic number.

It is not a de Polignac number, because 689765729 - 2²⁰ = 688717153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (689765723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9321122 + ... + 9321195.

It is an arithmetic number, because the mean of its divisors is an integer number (177102021).

Almost surely, 2^689765729 is an apocalyptic number.

It is an amenable number.

689765729 is a deficient number, since it is larger than the sum of its proper divisors (18642355).

689765729 is a wasteful number, since it uses less digits than its factorization.

689765729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18642354.

The product of its digits is 11430720, while the sum is 59.

The square root of 689765729 is about 26263.3914222821. The cubic root of 689765729 is about 883.5555737319. Note that the first 4 decimals are identical.

The spelling of 689765729 in words is "six hundred eighty-nine million, seven hundred sixty-five thousand, seven hundred twenty-nine".