689651521 has 4 divisors (see below), whose sum is σ = 742701652. Its totient is φ = 636601392.

The previous prime is 689651509. The next prime is 689651537. The reversal of 689651521 is 125156986.

689651521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 82719025 + 606932496 = 9095^2 + 24636^2 .

It is a cyclic number.

It is not a de Polignac number, because 689651521 - 2⁵ = 689651489 is a prime.

It is a super-3 number, since 3×689651521³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (689651551) 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, 26525046 + ... + 26525071.

It is an arithmetic number, because the mean of its divisors is an integer number (185675413).

Almost surely, 2^689651521 is an apocalyptic number.

It is an amenable number.

689651521 is a deficient number, since it is larger than the sum of its proper divisors (53050131).

689651521 is a wasteful number, since it uses less digits than its factorization.

689651521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53050130.

The product of its digits is 129600, while the sum is 43.

The square root of 689651521 is about 26261.2170510051. The cubic root of 689651521 is about 883.5068061187.

The spelling of 689651521 in words is "six hundred eighty-nine million, six hundred fifty-one thousand, five hundred twenty-one".