688607999 has 4 divisors (see below), whose sum is σ = 707219064. Its totient is φ = 669996936.

The previous prime is 688607957. The next prime is 688608049. The reversal of 688607999 is 999706886.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-688607999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688607099) 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 in 3 ways as a sum of consecutive naturals, for example, 9305477 + ... + 9305550.

It is an arithmetic number, because the mean of its divisors is an integer number (176804766).

Almost surely, 2^688607999 is an apocalyptic number.

688607999 is a deficient number, since it is larger than the sum of its proper divisors (18611065).

688607999 is a wasteful number, since it uses less digits than its factorization.

688607999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18611064.

The product of its (nonzero) digits is 11757312, while the sum is 62.

The square root of 688607999 is about 26241.3414100728. The cubic root of 688607999 is about 883.0609653995.

The spelling of 688607999 in words is "six hundred eighty-eight million, six hundred seven thousand, nine hundred ninety-nine".