688649823 has 8 divisors (see below), whose sum is σ = 1020222000. Its totient is φ = 459099864.

The previous prime is 688649783. The next prime is 688649827. The reversal of 688649823 is 328946886.

It is not a de Polignac number, because 688649823 - 2¹⁰ = 688648799 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 688649823.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688649827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12752748 + ... + 12752801.

It is an arithmetic number, because the mean of its divisors is an integer number (127527750).

Almost surely, 2^688649823 is an apocalyptic number.

688649823 is a deficient number, since it is larger than the sum of its proper divisors (331572177).

688649823 is a wasteful number, since it uses less digits than its factorization.

688649823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25505558 (or 25505552 counting only the distinct ones).

The product of its digits is 3981312, while the sum is 54.

The square root of 688649823 is about 26242.1383084534. The cubic root of 688649823 is about 883.0788432023.

It can be divided in two parts, 68864 and 9823, that added together give a palindrome (78687).

The spelling of 688649823 in words is "six hundred eighty-eight million, six hundred forty-nine thousand, eight hundred twenty-three".