684155441 has 2 divisors, whose sum is σ = 684155442. Its totient is φ = 684155440.

The previous prime is 684155431. The next prime is 684155509. The reversal of 684155441 is 144551486.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 619014400 + 65141041 = 24880^2 + 8071^2 .

It is a cyclic number.

It is not a de Polignac number, because 684155441 - 2⁶ = 684155377 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 684155395 and 684155404.

It is not a weakly prime, because it can be changed into another prime (684155431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342077720 + 342077721.

It is an arithmetic number, because the mean of its divisors is an integer number (342077721).

Almost surely, 2^684155441 is an apocalyptic number.

It is an amenable number.

684155441 is a deficient number, since it is larger than the sum of its proper divisors (1).

684155441 is an equidigital number, since it uses as much as digits as its factorization.

684155441 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 76800, while the sum is 38.

The square root of 684155441 is about 26156.3652100211. The cubic root of 684155441 is about 881.1535496205.

The spelling of 684155441 in words is "six hundred eighty-four million, one hundred fifty-five thousand, four hundred forty-one".