688547491 has 2 divisors, whose sum is σ = 688547492. Its totient is φ = 688547490.

The previous prime is 688547449. The next prime is 688547501. The reversal of 688547491 is 194745886.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 688547491 - 2⁹ = 688546979 is a prime.

It is not a weakly prime, because it can be changed into another prime (688547411) 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, 344273745 + 344273746.

It is an arithmetic number, because the mean of its divisors is an integer number (344273746).

Almost surely, 2^688547491 is an apocalyptic number.

688547491 is a deficient number, since it is larger than the sum of its proper divisors (1).

688547491 is an equidigital number, since it uses as much as digits as its factorization.

688547491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1935360, while the sum is 52.

The square root of 688547491 is about 26240.1884711219. The cubic root of 688547491 is about 883.0350997797.

The spelling of 688547491 in words is "six hundred eighty-eight million, five hundred forty-seven thousand, four hundred ninety-one".