685621915776 has 1280 divisors, whose sum is σ = 2650090037760. Its totient is φ = 171323817984.

The previous prime is 685621915751. The next prime is 685621915777. The reversal of 685621915776 is 677519126586.

685621915776 is a `hidden beast` number, since 6 + 8 + 56 + 2 + 1 + 9 + 1 + 577 + 6 = 666.

It is a super-2 number, since 2×685621915776² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (685621915777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 1049956666 + ... + 1049957318.

It is an arithmetic number, because the mean of its divisors is an integer number (2070382842).

Almost surely, 2^685621915776 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 685621915776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1325045018880).

685621915776 is an abundant number, since it is smaller than the sum of its proper divisors (1964468121984).

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

685621915776 is a wasteful number, since it uses less digits than its factorization.

685621915776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 763 (or 742 counting only the distinct ones).

The product of its digits is 38102400, while the sum is 63.

The spelling of 685621915776 in words is "six hundred eighty-five billion, six hundred twenty-one million, nine hundred fifteen thousand, seven hundred seventy-six".