7821280656 has 240 divisors, whose sum is σ = 25959132160. Its totient is φ = 2151152640.

The previous prime is 7821280603. The next prime is 7821280673. The reversal of 7821280656 is 6560821287.

It is a super-2 number, since 2×7821280656² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7155246 + ... + 7156338.

Almost surely, 2^7821280656 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 7821280656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12979566080).

7821280656 is an abundant number, since it is smaller than the sum of its proper divisors (18137851504).

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

7821280656 is a wasteful number, since it uses less digits than its factorization.

7821280656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1374 (or 1365 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The square root of 7821280656 is about 88438.0045907866. The cubic root of 7821280656 is about 1984.9944191693.

The spelling of 7821280656 in words is "seven billion, eight hundred twenty-one million, two hundred eighty thousand, six hundred fifty-six".