688861478991 has 32 divisors (see below), whose sum is σ = 1067199536128. Its totient is φ = 387074039040.

The previous prime is 688861478989. The next prime is 688861478999. The reversal of 688861478991 is 199874168886.

It is not a de Polignac number, because 688861478991 - 2¹ = 688861478989 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 (688861478999) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4631910 + ... + 4778316.

It is an arithmetic number, because the mean of its divisors is an integer number (33349985504).

Almost surely, 2^688861478991 is an apocalyptic number.

688861478991 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

688861478991 is a deficient number, since it is larger than the sum of its proper divisors (378338057137).

688861478991 is a wasteful number, since it uses less digits than its factorization.

688861478991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150151.

The product of its digits is 334430208, while the sum is 75.

The spelling of 688861478991 in words is "six hundred eighty-eight billion, eight hundred sixty-one million, four hundred seventy-eight thousand, nine hundred ninety-one".