681563520 has 384 divisors, whose sum is σ = 2657940480. Its totient is φ = 159436800.

The previous prime is 681563479. The next prime is 681563527. The reversal of 681563520 is 25365186.

681563520 is a `hidden beast` number, since 6 + 8 + 15 + 635 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681563527) 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, 1963987 + ... + 1964333.

It is an arithmetic number, because the mean of its divisors is an integer number (6921720).

Almost surely, 2^681563520 is an apocalyptic number.

681563520 is a gapful number since it is divisible by the number (60) 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 681563520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1328970240).

681563520 is an abundant number, since it is smaller than the sum of its proper divisors (1976376960).

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

681563520 is a wasteful number, since it uses less digits than its factorization.

681563520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414 (or 399 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The square root of 681563520 is about 26106.7715353699. The cubic root of 681563520 is about 880.0393921760.

The spelling of 681563520 in words is "six hundred eighty-one million, five hundred sixty-three thousand, five hundred twenty".