681123564 has 288 divisors, whose sum is σ = 2139830784. Its totient is φ = 180111360.

The previous prime is 681123563. The next prime is 681123629. The reversal of 681123564 is 465321186.

It is a happy number.

681123564 is a `hidden beast` number, since 6 + 81 + 12 + 3 + 564 = 666.

681123564 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

Its product of digits (34560) is a multiple of the sum of its prime divisors (192).

It is not an unprimeable number, because it can be changed into a prime (681123563) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 8206267 + ... + 8206349.

It is an arithmetic number, because the mean of its divisors is an integer number (7429968).

Almost surely, 2^681123564 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 681123564, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1069915392).

681123564 is an abundant number, since it is smaller than the sum of its proper divisors (1458707220).

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

681123564 is a wasteful number, since it uses less digits than its factorization.

681123564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197 (or 192 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 681123564 is about 26098.3440854013. The cubic root of 681123564 is about 879.8499933704.

The spelling of 681123564 in words is "six hundred eighty-one million, one hundred twenty-three thousand, five hundred sixty-four".