684663366481 has 2 divisors, whose sum is σ = 684663366482. Its totient is φ = 684663366480.

The previous prime is 684663366479. The next prime is 684663366493. The reversal of 684663366481 is 184663366486.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 407267330625 + 277396035856 = 638175^2 + 526684^2 .

It is a cyclic number.

It is not a de Polignac number, because 684663366481 - 2¹ = 684663366479 is a prime.

It is a super-2 number, since 2×684663366481² (a number of 24 digits) contains 22 as substring.

Together with 684663366479, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (684663366181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342331683240 + 342331683241.

It is an arithmetic number, because the mean of its divisors is an integer number (342331683241).

Almost surely, 2^684663366481 is an apocalyptic number.

It is an amenable number.

684663366481 is a deficient number, since it is larger than the sum of its proper divisors (1).

684663366481 is an equidigital number, since it uses as much as digits as its factorization.

684663366481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 71663616, while the sum is 61.

The spelling of 684663366481 in words is "six hundred eighty-four billion, six hundred sixty-three million, three hundred sixty-six thousand, four hundred eighty-one".