688905389 has 2 divisors, whose sum is σ = 688905390. Its totient is φ = 688905388.

The previous prime is 688905383. The next prime is 688905419. The reversal of 688905389 is 983509886.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 672364900 + 16540489 = 25930^2 + 4067^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-688905389 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688905383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344452694 + 344452695.

It is an arithmetic number, because the mean of its divisors is an integer number (344452695).

Almost surely, 2^688905389 is an apocalyptic number.

It is an amenable number.

688905389 is a deficient number, since it is larger than the sum of its proper divisors (1).

688905389 is an equidigital number, since it uses as much as digits as its factorization.

688905389 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3732480, while the sum is 56.

The square root of 688905389 is about 26247.0072389215. The cubic root of 688905389 is about 883.1880699858.

The spelling of 688905389 in words is "six hundred eighty-eight million, nine hundred five thousand, three hundred eighty-nine".