688735849 has 2 divisors, whose sum is σ = 688735850. Its totient is φ = 688735848.

The previous prime is 688735843. The next prime is 688735891. The reversal of 688735849 is 948537886.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 639735849 + 49000000 = 25293^2 + 7000^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-688735849 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 688735793 and 688735802.

It is not a weakly prime, because it can be changed into another prime (688735843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344367924 + 344367925.

It is an arithmetic number, because the mean of its divisors is an integer number (344367925).

Almost surely, 2^688735849 is an apocalyptic number.

It is an amenable number.

688735849 is a deficient number, since it is larger than the sum of its proper divisors (1).

688735849 is an equidigital number, since it uses as much as digits as its factorization.

688735849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11612160, while the sum is 58.

The square root of 688735849 is about 26243.7773386378. Note that the first 3 decimals coincide. The cubic root of 688735849 is about 883.1156130162.

The spelling of 688735849 in words is "six hundred eighty-eight million, seven hundred thirty-five thousand, eight hundred forty-nine".