681284240 has 240 divisors, whose sum is σ = 2057212080. Its totient is φ = 207728640.

The previous prime is 681284239. The next prime is 681284243. The reversal of 681284240 is 42482186.

It can be written as a sum of positive squares in 8 ways, for example, as 78287104 + 602997136 = 8848^2 + 24556^2 .

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 681284240.

It is not an unprimeable number, because it can be changed into a prime (681284243) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1477610 + ... + 1478070.

It is an arithmetic number, because the mean of its divisors is an integer number (8571717).

Almost surely, 2^681284240 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 681284240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1028606040).

681284240 is an abundant number, since it is smaller than the sum of its proper divisors (1375927840).

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

681284240 is a wasteful number, since it uses less digits than its factorization.

681284240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 530 (or 517 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 35.

The square root of 681284240 is about 26101.4221834750. The cubic root of 681284240 is about 879.9191730171.

The spelling of 681284240 in words is "six hundred eighty-one million, two hundred eighty-four thousand, two hundred forty".