6561551651 has 2 divisors, whose sum is σ = 6561551652. Its totient is φ = 6561551650.

The previous prime is 6561551641. The next prime is 6561551653. The reversal of 6561551651 is 1561551656.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6561551651 - 2⁶ = 6561551587 is a prime.

Together with 6561551653, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 6561551599 and 6561551608.

It is not a weakly prime, because it can be changed into another prime (6561551653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3280775825 + 3280775826.

It is an arithmetic number, because the mean of its divisors is an integer number (3280775826).

Almost surely, 2^6561551651 is an apocalyptic number.

6561551651 is a deficient number, since it is larger than the sum of its proper divisors (1).

6561551651 is an equidigital number, since it uses as much as digits as its factorization.

6561551651 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 135000, while the sum is 41.

The square root of 6561551651 is about 81003.4051815107. The cubic root of 6561551651 is about 1872.1279075123.

The spelling of 6561551651 in words is "six billion, five hundred sixty-one million, five hundred fifty-one thousand, six hundred fifty-one".