681528640 has 224 divisors, whose sum is σ = 1935601920. Its totient is φ = 226000896.

The previous prime is 681528637. The next prime is 681528671. The reversal of 681528640 is 46825186.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 681528593 and 681528602.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 1626351 + ... + 1626769.

It is an arithmetic number, because the mean of its divisors is an integer number (8641080).

Almost surely, 2^681528640 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 681528640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (967800960).

681528640 is an abundant number, since it is smaller than the sum of its proper divisors (1254073280).

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

681528640 is a wasteful number, since it uses less digits than its factorization.

681528640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 489 (or 479 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 40.

The square root of 681528640 is about 26106.1035009057. The cubic root of 681528640 is about 880.0243794899.

The spelling of 681528640 in words is "six hundred eighty-one million, five hundred twenty-eight thousand, six hundred forty".