688695149 has 2 divisors, whose sum is σ = 688695150. Its totient is φ = 688695148.

The previous prime is 688695131. The next prime is 688695151. The reversal of 688695149 is 941596886.

It is a happy number.

688695149 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 688695049 + 100 = 26243^2 + 10^2 .

It is a cyclic number.

It is not a de Polignac number, because 688695149 - 2⁸ = 688694893 is a prime.

It is a super-2 number, since 2×688695149² = 948602016512264402, which contains 22 as substring.

Together with 688695151, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 688695094 and 688695103.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688695179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344347574 + 344347575.

It is an arithmetic number, because the mean of its divisors is an integer number (344347575).

Almost surely, 2^688695149 is an apocalyptic number.

It is an amenable number.

688695149 is a deficient number, since it is larger than the sum of its proper divisors (1).

688695149 is an equidigital number, since it uses as much as digits as its factorization.

688695149 is an odious number, because the sum of its binary digits is odd.

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

The square root of 688695149 is about 26243.0019052699. The cubic root of 688695149 is about 883.0982171290.

The spelling of 688695149 in words is "six hundred eighty-eight million, six hundred ninety-five thousand, one hundred forty-nine".