7982561664 has 672 divisors, whose sum is σ = 30248381520. Its totient is φ = 2052864000.

The previous prime is 7982561647. The next prime is 7982561669. The reversal of 7982561664 is 4661652897.

7982561664 is a `hidden beast` number, since 79 + 8 + 2 + 561 + 6 + 6 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (54).

Its product of digits (4354560) is a multiple of the sum of its prime factors (162).

It is a self number, because there is not a number n which added to its sum of digits gives 7982561664.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7982561669) by changing a digit.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 79035214 + ... + 79035314.

Almost surely, 2^7982561664 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 7982561664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15124190760).

7982561664 is an abundant number, since it is smaller than the sum of its proper divisors (22265819856).

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

7982561664 is a wasteful number, since it uses less digits than its factorization.

7982561664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 124 counting only the distinct ones).

The product of its digits is 4354560, while the sum is 54.

The square root of 7982561664 is about 89345.1826569290. The cubic root of 7982561664 is about 1998.5457481654.

The spelling of 7982561664 in words is "seven billion, nine hundred eighty-two million, five hundred sixty-one thousand, six hundred sixty-four".