688986889 has 2 divisors, whose sum is σ = 688986890. Its totient is φ = 688986888.

The previous prime is 688986847. The next prime is 688986913. The reversal of 688986889 is 988689886.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 617025600 + 71961289 = 24840^2 + 8483^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-688986889 is a prime.

688986889 is a strobogrammatic number because it is the same when read upside-down.

It is not a weakly prime, because it can be changed into another prime (688986839) 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, 344493444 + 344493445.

It is an arithmetic number, because the mean of its divisors is an integer number (344493445).

Almost surely, 2^688986889 is an apocalyptic number.

It is an amenable number.

688986889 is a deficient number, since it is larger than the sum of its proper divisors (1).

688986889 is an equidigital number, since it uses as much as digits as its factorization.

688986889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 95551488, while the sum is 70.

The square root of 688986889 is about 26248.5597509654. The cubic root of 688986889 is about 883.2228967271. Note that the first 3 decimals are identical.

The spelling of 688986889 in words is "six hundred eighty-eight million, nine hundred eighty-six thousand, eight hundred eighty-nine".