6499081961509 has 12 divisors (see below), whose sum is σ = 6735840890796. Its totient is φ = 6268382040128.

The previous prime is 6499081961507. The next prime is 6499081961543. The reversal of 6499081961509 is 9051691809946.

It can be written as a sum of positive squares in 2 ways, for example, as 5173122802500 + 1325959159009 = 2274450^2 + 1151503^2 .

It is not a de Polignac number, because 6499081961509 - 2¹ = 6499081961507 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 (6499081961501) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17428864 + ... + 17797849.

It is an arithmetic number, because the mean of its divisors is an integer number (561320074233).

Almost surely, 2^{6499081961509} is an apocalyptic number.

It is an amenable number.

6499081961509 is a deficient number, since it is larger than the sum of its proper divisors (236758929287).

6499081961509 is an equidigital number, since it uses as much as digits as its factorization.

6499081961509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35226884 (or 35226825 counting only the distinct ones).

The product of its (nonzero) digits is 37791360, while the sum is 67.

The spelling of 6499081961509 in words is "six trillion, four hundred ninety-nine billion, eighty-one million, nine hundred sixty-one thousand, five hundred nine".