7978642560 has 672 divisors, whose sum is σ = 33362185500. Its totient is φ = 1818464256.

The previous prime is 7978642549. The next prime is 7978642703. The reversal of 7978642560 is 652468797.

7978642560 is a `hidden beast` number, since 7 + 9 + 78 + 6 + 4 + 2 + 560 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 7958067264 + 20575296 = 89208^2 + 4536^2 .

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).

It is a junction number, because it is equal to n+sod(n) for n = 7978642497 and 7978642506.

It is an unprimeable number.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 22861266 + ... + 22861614.

Almost surely, 2^7978642560 is an apocalyptic number.

7978642560 is a gapful number since it is divisible by the number (70) 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 7978642560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16681092750).

7978642560 is an abundant number, since it is smaller than the sum of its proper divisors (25383542940).

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

7978642560 is an equidigital number, since it uses as much as digits as its factorization.

7978642560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 400 (or 366 counting only the distinct ones).

The product of its (nonzero) digits is 5080320, while the sum is 54.

The square root of 7978642560 is about 89323.2475898632. The cubic root of 7978642560 is about 1998.2186271598.

The spelling of 7978642560 in words is "seven billion, nine hundred seventy-eight million, six hundred forty-two thousand, five hundred sixty".