851381746561 has 2 divisors, whose sum is σ = 851381746562. Its totient is φ = 851381746560.

The previous prime is 851381746559. The next prime is 851381746577. The reversal of 851381746561 is 165647183158.

851381746561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 644879665936 + 206502080625 = 803044^2 + 454425^2 .

It is a cyclic number.

It is not a de Polignac number, because 851381746561 - 2¹ = 851381746559 is a prime.

Together with 851381746559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (851381746541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 425690873280 + 425690873281.

It is an arithmetic number, because the mean of its divisors is an integer number (425690873281).

Almost surely, 2^851381746561 is an apocalyptic number.

It is an amenable number.

851381746561 is a deficient number, since it is larger than the sum of its proper divisors (1).

851381746561 is an equidigital number, since it uses as much as digits as its factorization.

851381746561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4838400, while the sum is 55.

The spelling of 851381746561 in words is "eight hundred fifty-one billion, three hundred eighty-one million, seven hundred forty-six thousand, five hundred sixty-one".