688909157 has 2 divisors, whose sum is σ = 688909158. Its totient is φ = 688909156.

The previous prime is 688909147. The next prime is 688909171. The reversal of 688909157 is 751909886.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 583415716 + 105493441 = 24154^2 + 10271^2 .

It is a cyclic number.

It is not a de Polignac number, because 688909157 - 2⁴ = 688909141 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 688909099 and 688909108.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688909147) 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, 344454578 + 344454579.

It is an arithmetic number, because the mean of its divisors is an integer number (344454579).

Almost surely, 2^688909157 is an apocalyptic number.

It is an amenable number.

688909157 is a deficient number, since it is larger than the sum of its proper divisors (1).

688909157 is an equidigital number, since it uses as much as digits as its factorization.

688909157 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1088640, while the sum is 53.

The square root of 688909157 is about 26247.0790184356. The cubic root of 688909157 is about 883.1896801955.

The spelling of 688909157 in words is "six hundred eighty-eight million, nine hundred nine thousand, one hundred fifty-seven".