688710109 has 2 divisors, whose sum is σ = 688710110. Its totient is φ = 688710108.

The previous prime is 688710089. The next prime is 688710131. The reversal of 688710109 is 901017886.

688710109 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 680427225 + 8282884 = 26085^2 + 2878^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-688710109 is a prime.

It is a super-2 number, since 2×688710109² = 948643228477583762, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688710199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344355054 + 344355055.

It is an arithmetic number, because the mean of its divisors is an integer number (344355055).

Almost surely, 2^688710109 is an apocalyptic number.

It is an amenable number.

688710109 is a deficient number, since it is larger than the sum of its proper divisors (1).

688710109 is an equidigital number, since it uses as much as digits as its factorization.

688710109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 40.

The square root of 688710109 is about 26243.2869320899. The cubic root of 688710109 is about 883.1046113726.

The spelling of 688710109 in words is "six hundred eighty-eight million, seven hundred ten thousand, one hundred nine".