6451561609 has 2 divisors, whose sum is σ = 6451561610. Its totient is φ = 6451561608.

The previous prime is 6451561561. The next prime is 6451561637. The reversal of 6451561609 is 9061651546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6189283584 + 262278025 = 78672^2 + 16195^2 .

It is a cyclic number.

It is not a de Polignac number, because 6451561609 - 2⁷ = 6451561481 is a prime.

It is not a weakly prime, because it can be changed into another prime (6451561309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3225780804 + 3225780805.

It is an arithmetic number, because the mean of its divisors is an integer number (3225780805).

Almost surely, 2^6451561609 is an apocalyptic number.

It is an amenable number.

6451561609 is a deficient number, since it is larger than the sum of its proper divisors (1).

6451561609 is an equidigital number, since it uses as much as digits as its factorization.

6451561609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 194400, while the sum is 43.

The square root of 6451561609 is about 80321.6135856346. The cubic root of 6451561609 is about 1861.6081987579.

The spelling of 6451561609 in words is "six billion, four hundred fifty-one million, five hundred sixty-one thousand, six hundred nine".