6481128991 has 16 divisors (see below), whose sum is σ = 6837811200. Its totient is φ = 6130906848.

The previous prime is 6481128971. The next prime is 6481129001. The reversal of 6481128991 is 1998211846.

It is a cyclic number.

It is not a de Polignac number, because 6481128991 - 2⁵ = 6481128959 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6481128971) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1519620 + ... + 1523878.

It is an arithmetic number, because the mean of its divisors is an integer number (427363200).

Almost surely, 2^6481128991 is an apocalyptic number.

6481128991 is a deficient number, since it is larger than the sum of its proper divisors (356682209).

6481128991 is a wasteful number, since it uses less digits than its factorization.

6481128991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4998.

The product of its digits is 248832, while the sum is 49.

The square root of 6481128991 is about 80505.4593863050. The cubic root of 6481128991 is about 1864.4477700483.

The spelling of 6481128991 in words is "six billion, four hundred eighty-one million, one hundred twenty-eight thousand, nine hundred ninety-one".