6561316251 has 16 divisors (see below), whose sum is σ = 11109107200. Its totient is φ = 3749323464.

The previous prime is 6561316247. The next prime is 6561316271. The reversal of 6561316251 is 1526131656.

6561316251 is a `hidden beast` number, since 6 + 5 + 613 + 16 + 25 + 1 = 666.

It is not a de Polignac number, because 6561316251 - 2² = 6561316247 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6561316241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17357791 + ... + 17358168.

It is an arithmetic number, because the mean of its divisors is an integer number (694319200).

Almost surely, 2^6561316251 is an apocalyptic number.

6561316251 is a deficient number, since it is larger than the sum of its proper divisors (4547790949).

6561316251 is a wasteful number, since it uses less digits than its factorization.

6561316251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34715975 (or 34715969 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 6561316251 is about 81001.9521431428. The cubic root of 6561316251 is about 1872.1055193027.

The spelling of 6561316251 in words is "six billion, five hundred sixty-one million, three hundred sixteen thousand, two hundred fifty-one".