688391693892 has 144 divisors (see below), whose sum is σ = 2070416030592. Its totient is φ = 188745914880.

The previous prime is 688391693861. The next prime is 688391693897. The reversal of 688391693892 is 298396193886.

688391693892 is a `hidden beast` number, since 6 + 8 + 83 + 9 + 169 + 389 + 2 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 688391693892.

It is not an unprimeable number, because it can be changed into a prime (688391693897) 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 47 ways as a sum of consecutive naturals, for example, 174967 + ... + 1186337.

Almost surely, 2^688391693892 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 688391693892, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1035208015296).

688391693892 is an abundant number, since it is smaller than the sum of its proper divisors (1382024336700).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

688391693892 is a wasteful number, since it uses less digits than its factorization.

688391693892 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1011498 (or 1011493 counting only the distinct ones).

The product of its digits is 241864704, while the sum is 72.

The spelling of 688391693892 in words is "six hundred eighty-eight billion, three hundred ninety-one million, six hundred ninety-three thousand, eight hundred ninety-two".