681521851296 has 336 divisors, whose sum is σ = 2363406141600. Its totient is φ = 190634549760.

The previous prime is 681521851207. The next prime is 681521851303. The reversal of 681521851296 is 692158125186.

681521851296 is a `hidden beast` number, since 6 + 8 + 15 + 21 + 8 + 512 + 96 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 3233755 + ... + 3438053.

It is an arithmetic number, because the mean of its divisors is an integer number (7033946850).

Almost surely, 2^681521851296 is an apocalyptic number.

681521851296 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 681521851296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1181703070800).

681521851296 is an abundant number, since it is smaller than the sum of its proper divisors (1681884290304).

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

681521851296 is a wasteful number, since it uses less digits than its factorization.

681521851296 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204351 (or 204328 counting only the distinct ones).

The product of its digits is 2073600, while the sum is 54.

The spelling of 681521851296 in words is "six hundred eighty-one billion, five hundred twenty-one million, eight hundred fifty-one thousand, two hundred ninety-six".