688731871 has 2 divisors, whose sum is σ = 688731872. Its totient is φ = 688731870.

The previous prime is 688731853. The next prime is 688731917. The reversal of 688731871 is 178137886.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 688731871 - 2⁹ = 688731359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688731811) 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, 344365935 + 344365936.

It is an arithmetic number, because the mean of its divisors is an integer number (344365936).

Almost surely, 2^688731871 is an apocalyptic number.

688731871 is a deficient number, since it is larger than the sum of its proper divisors (1).

688731871 is an equidigital number, since it uses as much as digits as its factorization.

688731871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 451584, while the sum is 49.

The square root of 688731871 is about 26243.7015491337. The cubic root of 688731871 is about 883.1139127801.

The spelling of 688731871 in words is "six hundred eighty-eight million, seven hundred thirty-one thousand, eight hundred seventy-one".