688948109 has 2 divisors, whose sum is σ = 688948110. Its totient is φ = 688948108.

The previous prime is 688948087. The next prime is 688948111. The reversal of 688948109 is 901849886.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 599172484 + 89775625 = 24478^2 + 9475^2 .

It is a cyclic number.

It is not a de Polignac number, because 688948109 - 2¹⁶ = 688882573 is a prime.

Together with 688948111, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688948129) 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, 344474054 + 344474055.

It is an arithmetic number, because the mean of its divisors is an integer number (344474055).

Almost surely, 2^688948109 is an apocalyptic number.

It is an amenable number.

688948109 is a deficient number, since it is larger than the sum of its proper divisors (1).

688948109 is an equidigital number, since it uses as much as digits as its factorization.

688948109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 995328, while the sum is 53.

The square root of 688948109 is about 26247.8210333734. The cubic root of 688948109 is about 883.2063255233.

The spelling of 688948109 in words is "six hundred eighty-eight million, nine hundred forty-eight thousand, one hundred nine".