6491007561 has 4 divisors (see below), whose sum is σ = 8654676752. Its totient is φ = 4327338372.

The previous prime is 6491007533. The next prime is 6491007631. The reversal of 6491007561 is 1657001946.

6491007561 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 6491007561 - 2¹⁷ = 6490876489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6491007461) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1081834591 + ... + 1081834596.

It is an arithmetic number, because the mean of its divisors is an integer number (2163669188).

Almost surely, 2^6491007561 is an apocalyptic number.

It is an amenable number.

6491007561 is a deficient number, since it is larger than the sum of its proper divisors (2163669191).

6491007561 is a wasteful number, since it uses less digits than its factorization.

6491007561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2163669190.

The product of its (nonzero) digits is 45360, while the sum is 39.

The square root of 6491007561 is about 80566.7894420524. The cubic root of 6491007561 is about 1865.3945561256.

The spelling of 6491007561 in words is "six billion, four hundred ninety-one million, seven thousand, five hundred sixty-one".