651566851581641 has 2 divisors, whose sum is σ = 651566851581642. Its totient is φ = 651566851581640.

The previous prime is 651566851581589. The next prime is 651566851581643. The reversal of 651566851581641 is 146185158665156.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 333224178116041 + 318342673465600 = 18254429^2 + 17842160^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-651566851581641 is a prime.

It is a Sophie Germain prime.

Together with 651566851581643, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (651566851581643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 325783425790820 + 325783425790821.

It is an arithmetic number, because the mean of its divisors is an integer number (325783425790821).

Almost surely, 2^{651566851581641} is an apocalyptic number.

It is an amenable number.

651566851581641 is a deficient number, since it is larger than the sum of its proper divisors (1).

651566851581641 is an equidigital number, since it uses as much as digits as its factorization.

651566851581641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 207360000, while the sum is 68.

The spelling of 651566851581641 in words is "six hundred fifty-one trillion, five hundred sixty-six billion, eight hundred fifty-one million, five hundred eighty-one thousand, six hundred forty-one".