685449679824 has 960 divisors, whose sum is σ = 2520213696000. Its totient is φ = 172595404800.

The previous prime is 685449679823. The next prime is 685449679829. The reversal of 685449679824 is 428976944586.

685449679824 is a `hidden beast` number, since 6 + 8 + 54 + 496 + 7 + 9 + 82 + 4 = 666.

It is a super-2 number, since 2×685449679824² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685449679823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2439322564 + ... + 2439322844.

It is an arithmetic number, because the mean of its divisors is an integer number (2625222600).

Almost surely, 2^685449679824 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 685449679824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1260106848000).

685449679824 is an abundant number, since it is smaller than the sum of its proper divisors (1834764016176).

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

685449679824 is a wasteful number, since it uses less digits than its factorization.

685449679824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 489 (or 466 counting only the distinct ones).

The product of its digits is 836075520, while the sum is 72.

The spelling of 685449679824 in words is "six hundred eighty-five billion, four hundred forty-nine million, six hundred seventy-nine thousand, eight hundred twenty-four".