689312509 has 2 divisors, whose sum is σ = 689312510. Its totient is φ = 689312508.

The previous prime is 689312471. The next prime is 689312527. The reversal of 689312509 is 905213986.

It is a happy number.

689312509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 464402500 + 224910009 = 21550^2 + 14997^2 .

It is a cyclic number.

It is not a de Polignac number, because 689312509 - 2²⁷ = 555094781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (689312009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344656254 + 344656255.

It is an arithmetic number, because the mean of its divisors is an integer number (344656255).

Almost surely, 2^689312509 is an apocalyptic number.

It is an amenable number.

689312509 is a deficient number, since it is larger than the sum of its proper divisors (1).

689312509 is an equidigital number, since it uses as much as digits as its factorization.

689312509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 116640, while the sum is 43.

The square root of 689312509 is about 26254.7616443189. The cubic root of 689312509 is about 883.3620139100.

The spelling of 689312509 in words is "six hundred eighty-nine million, three hundred twelve thousand, five hundred nine".