8561006640 has 480 divisors, whose sum is σ = 31938955776. Its totient is φ = 2125854720.

The previous prime is 8561006639. The next prime is 8561006669. The reversal of 8561006640 is 466001658.

8561006640 is a `hidden beast` number, since 8 + 5 + 6 + 1 + 0 + 0 + 6 + 640 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 8561006595 and 8561006604.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 18331687 + ... + 18332153.

Almost surely, 2^8561006640 is an apocalyptic number.

8561006640 is a gapful number since it is divisible by the number (80) 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 8561006640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15969477888).

8561006640 is an abundant number, since it is smaller than the sum of its proper divisors (23377949136).

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

8561006640 is a wasteful number, since it uses less digits than its factorization.

8561006640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559 (or 541 counting only the distinct ones).

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

The square root of 8561006640 is about 92525.7079951297. The cubic root of 8561006640 is about 2045.6984273569.

The spelling of 8561006640 in words is "eight billion, five hundred sixty-one million, six thousand, six hundred forty".