688546649 has 4 divisors (see below), whose sum is σ = 786910464. Its totient is φ = 590182836.

The previous prime is 688546633. The next prime is 688546667. The reversal of 688546649 is 946645886.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 946645886 = 2 ⋅473322943.

It is a cyclic number.

It is not a de Polignac number, because 688546649 - 2⁴ = 688546633 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 688546594 and 688546603.

It is not an unprimeable number, because it can be changed into a prime (688546609) 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 in 3 ways as a sum of consecutive naturals, for example, 49181897 + ... + 49181910.

It is an arithmetic number, because the mean of its divisors is an integer number (196727616).

Almost surely, 2^688546649 is an apocalyptic number.

It is an amenable number.

688546649 is a deficient number, since it is larger than the sum of its proper divisors (98363815).

688546649 is an equidigital number, since it uses as much as digits as its factorization.

688546649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98363814.

The product of its digits is 9953280, while the sum is 56.

The square root of 688546649 is about 26240.1724270249. The cubic root of 688546649 is about 883.0347398356.

The spelling of 688546649 in words is "six hundred eighty-eight million, five hundred forty-six thousand, six hundred forty-nine".