6501991056 has 160 divisors (see below), whose sum is σ = 18910801536. Its totient is φ = 1907712000.

The previous prime is 6501991051. The next prime is 6501991063.

6501991056 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 6501990999 and 6501991017.

It is not an unprimeable number, because it can be changed into a prime (6501991051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4707486 + ... + 4708866.

Almost surely, 2^6501991056 is an apocalyptic number.

6501991056 is a gapful number since it is divisible by the number (66) 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 6501991056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9455400768).

6501991056 is an abundant number, since it is smaller than the sum of its proper divisors (12408810480).

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

6501991056 is a wasteful number, since it uses less digits than its factorization.

6501991056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1681 (or 1675 counting only the distinct ones).

The product of its (nonzero) digits is 72900, while the sum is 42.

The square root of 6501991056 is about 80634.9245426571. The cubic root of 6501991056 is about 1866.4461137946.

The spelling of 6501991056 in words is "six billion, five hundred one million, nine hundred ninety-one thousand, fifty-six".