689555521 has 2 divisors, whose sum is σ = 689555522. Its totient is φ = 689555520.

The previous prime is 689555459. The next prime is 689555549. The reversal of 689555521 is 125555986.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 530795521 + 158760000 = 23039^2 + 12600^2 .

It is a cyclic number.

It is not a de Polignac number, because 689555521 - 2⁷ = 689555393 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (689555561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344777760 + 344777761.

It is an arithmetic number, because the mean of its divisors is an integer number (344777761).

Almost surely, 2^689555521 is an apocalyptic number.

It is an amenable number.

689555521 is a deficient number, since it is larger than the sum of its proper divisors (1).

689555521 is an equidigital number, since it uses as much as digits as its factorization.

689555521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 540000, while the sum is 46.

The square root of 689555521 is about 26259.3891970091. The cubic root of 689555521 is about 883.4658092835.

The spelling of 689555521 in words is "six hundred eighty-nine million, five hundred fifty-five thousand, five hundred twenty-one".